How to adjust a Diesel engine for best flight operation???????
10-12-2016, 06:51 AM
#1
Thread Starter
How to adjust a Diesel engine for best flight operation???????
Hello All:
I can not seem to be able to adjust a Diesel engine to run well in the air. It always goes way over compressed!! The last flight yesterday resulted in a run that was so over compressed that the engine quit during the flight, The plane was covered with BLACK residue at the end of the flight,
I had flown the first flight using the setting obtained from the last flying session. This proved to be to little compression. I increased the compression about 1/16 of a turn and all seemed good. As soon as the plane got up to speed. it became very over compressed.
Here is my starting drill:
Start the engine and allow it to warn up.
Adjust the needle valve and compression until the engine is running well. I increase the compression from a point where it is misfiring due to too little compression to where it stops misfiring. I also adjust the needle calve to where it is a bit more rich than the fastest engine speed. This results in an over compressed engine run. I have tried many variations of the above to no avail.
I am at wits end as to how to get a good run from my diesel engines! They are either too under compressed missing and slow, or they go vey over compressed in the air. In the past I considered launching the engine a bit rich, to permit it to unload in the air. I have backed off the compression prior to launch, this led to a miss, left the compression from where it ran well on the ground and this led to an over compressed condition. I increased the compression to compensate for unloading in the air and this resulted in a very over compressed engine!
How does one find ideal settings for a Diesel? What is your drill?
The engines in question are two new ST G20/.15D engines. I am running a wooden 7X6 prop for break in. Perhaps this prop has too little load thus making the engine very critical to adjust. Perhaps an 8X6 prop would help solve the problem. I have no trouble setting my MVVS D7 or engines with Davis conversions. What am I missing with the ST engines?
Help needed!!!!!
Tia,
Franchi
I can not seem to be able to adjust a Diesel engine to run well in the air. It always goes way over compressed!! The last flight yesterday resulted in a run that was so over compressed that the engine quit during the flight, The plane was covered with BLACK residue at the end of the flight,
I had flown the first flight using the setting obtained from the last flying session. This proved to be to little compression. I increased the compression about 1/16 of a turn and all seemed good. As soon as the plane got up to speed. it became very over compressed.
Here is my starting drill:
Start the engine and allow it to warn up.
Adjust the needle valve and compression until the engine is running well. I increase the compression from a point where it is misfiring due to too little compression to where it stops misfiring. I also adjust the needle calve to where it is a bit more rich than the fastest engine speed. This results in an over compressed engine run. I have tried many variations of the above to no avail.
I am at wits end as to how to get a good run from my diesel engines! They are either too under compressed missing and slow, or they go vey over compressed in the air. In the past I considered launching the engine a bit rich, to permit it to unload in the air. I have backed off the compression prior to launch, this led to a miss, left the compression from where it ran well on the ground and this led to an over compressed condition. I increased the compression to compensate for unloading in the air and this resulted in a very over compressed engine!
How does one find ideal settings for a Diesel? What is your drill?
The engines in question are two new ST G20/.15D engines. I am running a wooden 7X6 prop for break in. Perhaps this prop has too little load thus making the engine very critical to adjust. Perhaps an 8X6 prop would help solve the problem. I have no trouble setting my MVVS D7 or engines with Davis conversions. What am I missing with the ST engines?
Help needed!!!!!
Tia,
Franchi
10-12-2016, 11:06 PM
#2
I think that it could be a combination of things and everything also becomes a little more sensitive and critical on smaller props.
I would first find the optimum compression setting at a fully leaned out needle, this will then be you maximum compression setting, which you should never really use in order to be on the safe side. Try to mark that directly on the cylinder head, a small scratch/arrow is enough. So back off a little from this compression setting and now do the rest of the tuning with the needle only. If it misses in the air, as the engine unloads, it needs more fuel not a higher compression setting.
If this doesn't work, then try with a different fuel. The ignition improver is there in order to give you a less sensitive setting, perhaps it simply needs a little more of that.
Last resort is a larger prop, the compression setting will then be lower and everything is less critical.
I would first find the optimum compression setting at a fully leaned out needle, this will then be you maximum compression setting, which you should never really use in order to be on the safe side. Try to mark that directly on the cylinder head, a small scratch/arrow is enough. So back off a little from this compression setting and now do the rest of the tuning with the needle only. If it misses in the air, as the engine unloads, it needs more fuel not a higher compression setting.
If this doesn't work, then try with a different fuel. The ignition improver is there in order to give you a less sensitive setting, perhaps it simply needs a little more of that.
Last resort is a larger prop, the compression setting will then be lower and everything is less critical.
10-13-2016, 04:31 AM
#3
Thread Starter
Thanks for the reply.
Hello Mr. Cox:
Thank you for the reply!
I will try your suggestions asap! I have had very good luck in the past tuning Diesels. Perhaps I mistook the high speed missing of the engine for too little compression!!!!!
One of the tragedies of older age is that one forgets what one has learned! " I knew that" is often said after an attempted repair on a household appliance or automobile has been made by someone else.
Be well my friend,
Franchi
Thank you for the reply!
I will try your suggestions asap! I have had very good luck in the past tuning Diesels. Perhaps I mistook the high speed missing of the engine for too little compression!!!!!
One of the tragedies of older age is that one forgets what one has learned! " I knew that" is often said after an attempted repair on a household appliance or automobile has been made by someone else.
Be well my friend,
Franchi
10-13-2016, 08:16 AM
#4
Thread Starter
Engine tuning, what do next?
Hello:
Now that I have found what ideal settings for the compression and needle valve are, what do I do to start the engine? I leaned it out to max speed and adjusted the compression for maximum speed then backed the compression off. I have done this in the past and the engine went very over compressed while in flight. I thought that one should richen the mixture and increase the compression to compensate for the engine picking up speed when airborne. Like advancing the timing to compensate for gained airspeed. This has led to over compressed engines. Some have suggested that I increase compression, some say to decrease compression, richen the needle valve, do not make any changes. What do you recommend?
Last question: why is it easier to start this engine by hand than it is to start it by an electric starter?
Tia,
Franchi
Now that I have found what ideal settings for the compression and needle valve are, what do I do to start the engine? I leaned it out to max speed and adjusted the compression for maximum speed then backed the compression off. I have done this in the past and the engine went very over compressed while in flight. I thought that one should richen the mixture and increase the compression to compensate for the engine picking up speed when airborne. Like advancing the timing to compensate for gained airspeed. This has led to over compressed engines. Some have suggested that I increase compression, some say to decrease compression, richen the needle valve, do not make any changes. What do you recommend?
Last question: why is it easier to start this engine by hand than it is to start it by an electric starter?
Tia,
Franchi
10-13-2016, 08:40 PM
#5
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Hi Franchi,
The 'standard' method is to increase the compression slightly (ie advance the ignition) to account for the increase in RPM when flying. If this leads to 'over compression' (ie over advanced) then don't do it or at least not as much.
If I am reading your first post correctly you are getting the engine running well then richening the needle? This will also advance the ignition so if you do it too much you might end up over advanced as well (ie 'over compressed' for the needle setting).
Unlike a glow engine you don't need to richen a Diesel for the extra RPM airborne. If you want to run richer you would be better off setting the needle slightly richer then adjusting the compression to match ie increase the compression till the engine just stops missing (plus a bit more to allow for the RPM increase if it needs it).
Other than the black exhaust what are your symptoms of 'over compression'? Hard sounding with a loss of RPM? If it's missing that would be retarded ignition (under compressed).
The other cause of an engine going 'over compressed' in the air is heat, but this would normally happen on the ground as well. These engines can sometimes take a long time to completely warm up so they might continue getting hotter once airborne, and therefore go 'over compressed'.
How much running has your engine done? Lapped piston engines can take a lot of running to fully run in, in the mean time they can slowly increase temperature during the run. The extra heat advances the ignition giving the 'over compressed' symptoms
Does your engine get enough cooling air?
Can you run out a full tank of fuel on the ground without the engine 'over compressing'.
How does it sound at the end of the tank? A second or two of missing before it quits is normal, if it stops quick and harsh it may be hot.
In the day it wasn't unusual to have to send models off retarded (under compressed) and have them 'come in' after 10 or 20 seconds of flight. Have you tried sending the model off slightly under compressed?
I run 9 X 4 or 8 X 6 props on a .15 but that depends on the style of model and flying you are doing.
The ignition improver suggestion is a good one, 1 to 2% of Amsoil Cetane Boost is the usual recomendation if your fuel doesn't already have it.
Hope this helps,
Dave H
The 'standard' method is to increase the compression slightly (ie advance the ignition) to account for the increase in RPM when flying. If this leads to 'over compression' (ie over advanced) then don't do it or at least not as much.
If I am reading your first post correctly you are getting the engine running well then richening the needle? This will also advance the ignition so if you do it too much you might end up over advanced as well (ie 'over compressed' for the needle setting).
Unlike a glow engine you don't need to richen a Diesel for the extra RPM airborne. If you want to run richer you would be better off setting the needle slightly richer then adjusting the compression to match ie increase the compression till the engine just stops missing (plus a bit more to allow for the RPM increase if it needs it).
Other than the black exhaust what are your symptoms of 'over compression'? Hard sounding with a loss of RPM? If it's missing that would be retarded ignition (under compressed).
The other cause of an engine going 'over compressed' in the air is heat, but this would normally happen on the ground as well. These engines can sometimes take a long time to completely warm up so they might continue getting hotter once airborne, and therefore go 'over compressed'.
How much running has your engine done? Lapped piston engines can take a lot of running to fully run in, in the mean time they can slowly increase temperature during the run. The extra heat advances the ignition giving the 'over compressed' symptoms
Does your engine get enough cooling air?
Can you run out a full tank of fuel on the ground without the engine 'over compressing'.
How does it sound at the end of the tank? A second or two of missing before it quits is normal, if it stops quick and harsh it may be hot.
In the day it wasn't unusual to have to send models off retarded (under compressed) and have them 'come in' after 10 or 20 seconds of flight. Have you tried sending the model off slightly under compressed?
I run 9 X 4 or 8 X 6 props on a .15 but that depends on the style of model and flying you are doing.
The ignition improver suggestion is a good one, 1 to 2% of Amsoil Cetane Boost is the usual recomendation if your fuel doesn't already have it.
Hope this helps,
Dave H
01-14-2017, 02:43 PM
#6
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I run diesels much leaner than glow. A bigger prop usually helps with everything and I would run at least a 9" prop with a .15 7" is way small....
Ball park is about a 1/4 turn more compression and 1/2 turn richer on the needle to start vrs. flying settings. Every engine is different and after a while you learn exactly what they like. I write that down because I forget all of it when the plane sits for a year.....
Ball park is about a 1/4 turn more compression and 1/2 turn richer on the needle to start vrs. flying settings. Every engine is different and after a while you learn exactly what they like. I write that down because I forget all of it when the plane sits for a year.....
01-15-2017, 02:24 AM
#7
My Feedback: (1)
I might be wrong here but I thought our friend Franchi (aka Frank Mccune) was flying his diesels in control line models. That would necessitate richening the needle prior to launching. A 7" prop is quite suitable for a ST G20 .15D' I have three of them and they're fine little engines. It is also possible to have far too much DII (AMSOIL) in diesel fuel in hot climates and to get the symptoms he's reporting. Also I believe these are the G20-15D engines of which he's recently had the cylinders hard chromed. Perhaps they need more running in?
We usually use 1.0% AMSOIL (Ignition Improver = II) in high summer, and 1.5% in mid winter and inbetween to suit the day. The II controls how quickly the engine warms up from cold. Start it slightly under-compressed leave it that way and see how long it takes to stabilize. About 20 seconds is ideal. If it takes longer add DII, shorter use slightly less. This is pretty well particular to c/l models in hot climates. We use much less ignition improver because of the high Cetane rating of our Kero.
We usually use 1.0% AMSOIL (Ignition Improver = II) in high summer, and 1.5% in mid winter and inbetween to suit the day. The II controls how quickly the engine warms up from cold. Start it slightly under-compressed leave it that way and see how long it takes to stabilize. About 20 seconds is ideal. If it takes longer add DII, shorter use slightly less. This is pretty well particular to c/l models in hot climates. We use much less ignition improver because of the high Cetane rating of our Kero.
Last edited by qazimoto; 01-15-2017 at 02:19 PM.
01-15-2017, 07:06 AM
#8
I didn't see a mention of what fuel is being used. If not mixing your own fuel, it's kinda tough to control how much ignition improver is being used.
I use 2% Amsoil Cetane booster in my fuel. I'm using converted glow engines with RC throttles with larger than optimal choke sizes. Using more improver seems to help with starting and helps make the needle/comp settings less critical. I'm still pretty green with diesels, so as I "get it" further, I'll experiment with using less improver to see if it was a figment of my imagination or not (making my engine run better/easier to set).
I use 2% Amsoil Cetane booster in my fuel. I'm using converted glow engines with RC throttles with larger than optimal choke sizes. Using more improver seems to help with starting and helps make the needle/comp settings less critical. I'm still pretty green with diesels, so as I "get it" further, I'll experiment with using less improver to see if it was a figment of my imagination or not (making my engine run better/easier to set).
04-28-2017, 02:45 PM
#9
Thread Starter
Franchi's reply.
Hello all:
Just spent a delightful day flying my ST G20/.15D. When I quit, I was near to getting a good needle valve-compression setting.
The final flights were a bit over compressed and a bit lean. I had a black residue and later a brown residue on my plane after a few flights. Here ae some observations that I came up with for today. The next time that I fly this engine, I am going to lean it out and adjust the compression and needle valve for max rpms and then back off the compression just a bit. If this setting produces NO black exhaust residue after being run on the ground, then one must conclude that it is a good setting for in the air, ??????????????
I am going nuts trying to get a good setting. NO BLACK RESIDUE. During final flight of the day the engine sounded like it was a bit lean. Upon landing, the engine the tommy bar was too hot to touch. The compression had been increased to a point where all missing from being under compressed stopped. This still lead to a dark colour of exhaust residue rom over compression. If I put the plane up with a slight miss due to being under compressed, I do not have much power but, I have no dark exhaust residue.
I adjusted my Mate's Oliver Tigre to where it ran perfectly with a clear exhaust colour. Ah ha! We were using different fuel mixes!!! Nxt week, I will use his fuel to seed if this is the cause of my anguish! He is using a 9x6 prop and it appears to work very well. For some reason, I consider a 9x6 prop a bit too big for a .15 engine.
People have asked for more details concerning my set up:
Air plane full size flite streek controline. It is quite rapid with this engine and stunts very well
Engine ST G20-.15D side mounted on a profile.
Prop 8x4 plastic
Fuel DDD standard with 6oz. of castor added per gallon
Standard FAI lines 52' 6"
Engine mounted as a profile so cooling is not a problem.
Tank metal 3 oz. with uniflow
Temperature 81 deg.F or 28 deg.C ??????
I did purchase 6 wooden 8x6 props to try on this and my MVVS D7. This may help a bit???
Thanks to all who have taken the time to help me with my addiction. My flying Mate is also fascinated by Diesel engines so we have each other to turn to for help. Lol
Be well my friends,
Franchi
Just spent a delightful day flying my ST G20/.15D. When I quit, I was near to getting a good needle valve-compression setting.
The final flights were a bit over compressed and a bit lean. I had a black residue and later a brown residue on my plane after a few flights. Here ae some observations that I came up with for today. The next time that I fly this engine, I am going to lean it out and adjust the compression and needle valve for max rpms and then back off the compression just a bit. If this setting produces NO black exhaust residue after being run on the ground, then one must conclude that it is a good setting for in the air, ??????????????
I am going nuts trying to get a good setting. NO BLACK RESIDUE. During final flight of the day the engine sounded like it was a bit lean. Upon landing, the engine the tommy bar was too hot to touch. The compression had been increased to a point where all missing from being under compressed stopped. This still lead to a dark colour of exhaust residue rom over compression. If I put the plane up with a slight miss due to being under compressed, I do not have much power but, I have no dark exhaust residue.
I adjusted my Mate's Oliver Tigre to where it ran perfectly with a clear exhaust colour. Ah ha! We were using different fuel mixes!!! Nxt week, I will use his fuel to seed if this is the cause of my anguish! He is using a 9x6 prop and it appears to work very well. For some reason, I consider a 9x6 prop a bit too big for a .15 engine.
People have asked for more details concerning my set up:
Air plane full size flite streek controline. It is quite rapid with this engine and stunts very well
Engine ST G20-.15D side mounted on a profile.
Prop 8x4 plastic
Fuel DDD standard with 6oz. of castor added per gallon
Standard FAI lines 52' 6"
Engine mounted as a profile so cooling is not a problem.
Tank metal 3 oz. with uniflow
Temperature 81 deg.F or 28 deg.C ??????
I did purchase 6 wooden 8x6 props to try on this and my MVVS D7. This may help a bit???
Thanks to all who have taken the time to help me with my addiction. My flying Mate is also fascinated by Diesel engines so we have each other to turn to for help. Lol
Be well my friends,
Franchi
04-28-2017, 02:55 PM
#10
Thread Starter
Starting inverted Diesel engines??
Hello All:
The time has come for me to put an OS .40 with a Davis head into my ready to fly Nobler. Are there any special instruction and/or problems when starting an inverted Diesel?
This engine is mounted on a profile stunter and to start it, I choke it to get the fuel to the spray bar and then apply an electric starter. The engine starts instantly and needs no additional adjustments! Oh yes, one does not want ho hand flip this engine!!! If flooded, dire things will happen to one of your former digits! The exhaust residue is the same colour as what is produced by a glow engine.
This engine gives perfect stunt runs in the profile stunter.
Suggestions / comments ?
Franchi
The time has come for me to put an OS .40 with a Davis head into my ready to fly Nobler. Are there any special instruction and/or problems when starting an inverted Diesel?
This engine is mounted on a profile stunter and to start it, I choke it to get the fuel to the spray bar and then apply an electric starter. The engine starts instantly and needs no additional adjustments! Oh yes, one does not want ho hand flip this engine!!! If flooded, dire things will happen to one of your former digits! The exhaust residue is the same colour as what is produced by a glow engine.
This engine gives perfect stunt runs in the profile stunter.
Suggestions / comments ?
Franchi
04-29-2017, 07:40 AM
#11
PAW .09 RC, with muffler; 9x4 prop : 10500rpm
MVVS/Modela Junior, 2cc (0.12) RC, with muffler; 9x5 prop : 10500rpm
So for a .15 engine I would recommend a 9x6 or a 10x4 prop to start with. Tuning will be less critical and the overall handling is easier too. I quite like plastic/nylon props as they have a bit more of a fly-wheel effect and that helps the starting and idling a bit. You just have to deburr them a lot so that it doesn't cut your finger or gloves...
Last edited by Mr Cox; 04-29-2017 at 07:42 AM.
04-29-2017, 02:40 PM
#12
My Feedback: (1)
That sounds about right to me, certainly not a too large prop by any means. I usually prop my diesels for about 10-11000rpm on the ground. The tuning is easier and less sensitive/critical on larger props and it is also less demanding for the engine. For higher rpms the fuel and the amount of ignition improver are more important. Here are some typical prop sizes and rpms:
PAW .09 RC, with muffler; 9x4 prop : 10500rpm
MVVS/Modela Junior, 2cc (0.12) RC, with muffler; 9x5 prop : 10500rpm
So for a .15 engine I would recommend a 9x6 or a 10x4 prop to start with. Tuning will be less critical and the overall handling is easier too. I quite like plastic/nylon props as they have a bit more of a fly-wheel effect and that helps the starting and idling a bit. You just have to deburr them a lot so that it doesn't cut your finger or gloves...
PAW .09 RC, with muffler; 9x4 prop : 10500rpm
MVVS/Modela Junior, 2cc (0.12) RC, with muffler; 9x5 prop : 10500rpm
So for a .15 engine I would recommend a 9x6 or a 10x4 prop to start with. Tuning will be less critical and the overall handling is easier too. I quite like plastic/nylon props as they have a bit more of a fly-wheel effect and that helps the starting and idling a bit. You just have to deburr them a lot so that it doesn't cut your finger or gloves...
04-30-2017, 01:11 AM
#13
If it is not used for competitions (?) it still comes down to the type of plane and the set-up. There are other ways to increase line tension than pure speed, if line tension becomes problem. But an engine that is easier to tune on a 9x6 can also outperform a poorly tuned engine on a 8x6 prop. So I don't see any reasons to not try with a larger prop when one struggles to get it to run right on a smaller one.
04-30-2017, 04:16 AM
#14
My Feedback: (1)
If it is not used for competitions (?) it still comes down to the type of plane and the set-up. There are other ways to increase line tension than pure speed, if line tension becomes problem. But an engine that is easier to tune on a 9x6 can also outperform a poorly tuned engine on a 8x6 prop. So I don't see any reasons to not try with a larger prop when one struggles to get it to run right on a smaller one.
04-30-2017, 06:06 AM
#15
No, I don't have any of the Oliver or Super Tiger engines discussed here. I guess the fuel is the only source of error then, so the best would be to get some commercial fuel.
Since he's i having problems with overheating and too sensitive settings, I still think that it is a good idea to try a larger prop. It certainly will not hurt the engine if it is retuned for it.
Since he's i having problems with overheating and too sensitive settings, I still think that it is a good idea to try a larger prop. It certainly will not hurt the engine if it is retuned for it.
04-30-2017, 07:12 AM
#16
I should say first that I know little about diesels, and am reading this to learn more before I try out my PAW .06. I remember some of the team race guys using the old G15 STigers back in the 1970s. They all used the Cox .049 carbs I am presuming for better mileage. They were always beeping around undercompressed, and as soon as they warmed up in flight, the slightest hint of being overcompressed, they would shut them off. I think the props they used were like 7" dia.-8pitch" or so. Your OS .40 on the Nobler sounds great. Is it the LA? The team race guys all had their motors inverted with few problems. I would be careful to not flood it of course.
04-30-2017, 03:23 PM
#17
My Feedback: (1)
I should say first that I know little about diesels, and am reading this to learn more before I try out my PAW .06. I remember some of the team race guys using the old G15 STigers back in the 1970s. They all used the Cox .049 carbs I am presuming for better mileage. They were always beeping around undercompressed, and as soon as they warmed up in flight, the slightest hint of being overcompressed, they would shut them off. I think the props they used were like 7" dia.-8pitch" or so. Your OS .40 on the Nobler sounds great. Is it the LA? The team race guys all had their motors inverted with few problems. I would be careful to not flood it of course.
The pic shows one of my Oliver Tiger mk3s with a Cox TD 09 carby assembly.
05-04-2017, 11:06 AM
#18
One of the best points of using a diesel is the ease of tuning it for various prop sizes. Although many props would work, for a full-size Flite Streak I would use either an 8x6 or a 9x4.
I would save smaller props for airframes with less drag (like a team racer) and larger props for something like a scale airplane.
Of course this is personal preference...use what YOU want.
George
I would save smaller props for airframes with less drag (like a team racer) and larger props for something like a scale airplane.
Of course this is personal preference...use what YOU want.
George
03-21-2022, 02:27 AM
#19
Junior Member
Starting settings
I'm having difficuly starting an old AM-10. Can anyone send me the best compression and needle valve settings? Should the compression screw be mostly unscrewed (i.e. low compression) and I'd welcome any tips to get it started.
03-21-2022, 01:51 PM
#20
Without the fuel tank connected, and muffler removed, bring the piston up to just cover the exhaust port. Now squirt some fuel on the side of the piston and flip it over smartly. Increase the compression until you can get it to pop. You might need to add a drop or two of fuel every few flips.
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04-08-2022, 06:37 AM
#21
One thing that was not mentioned (at least I didn't see it) was the potential that the fuel had lost ether. He indicated that he was flying at an outside temperature of 81F, Ether can boil off at 77F. If you don't mix the fuel fresh for each flight and don't keep it and the tank in a cool place out of the sun as soon as you fill the tank the ether can start to evaporate. The ether not only is needed for starting but also cooling. Once it gets low (say below 20% ish) you get less cooling and can lead to an over compressed run. Since it seemed to run OK on the second blend my guess is low ether level in the fuel.
I like to keep my diesel fuel in a cooler with a few ice packs in the bottom, out of direct sun. I also keep the plane out of direct sun or cover it between flights in the summer to keep the fuel tank from getting warm.
On a Flite Streak size ship the 9" diameter prop is a better choice. Look up the article that Geroge Alrich (GMA) wrote on the Peacemaker full fuse version, That had an Olie 15 and 9x6 prop, he also gives a good fuel mix.
Best, DennisT
I like to keep my diesel fuel in a cooler with a few ice packs in the bottom, out of direct sun. I also keep the plane out of direct sun or cover it between flights in the summer to keep the fuel tank from getting warm.
On a Flite Streak size ship the 9" diameter prop is a better choice. Look up the article that Geroge Alrich (GMA) wrote on the Peacemaker full fuse version, That had an Olie 15 and 9x6 prop, he also gives a good fuel mix.
Best, DennisT
