ASP 180 FS will not rev above 7800  
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ASP 180 FS will not rev above 7800 - 5/4/2008 8:38:55 AM   
chris de jon


 

Posts: 38
Joined: 2/2/2003
From: australia, AUSTRALIA
Status: offline 		Good Day,
I have a problem with my Magnum 180 FS. It has around 50 flights and I use 17% synth + 2% castor. No nitro. I use on board glow up to 1/3 throttle.

I am using a Master 16 x 8.

The max revs I can get are 7800 on the ground before it leans and dies. The HS needle is about 1.25 turns out.
When tuning I noticed that pressing in on the needle increased revs. I have wrapped the threads on the needle with teflon and placed some fuel tube over the needle at the inlet junction.
Pressing the needle now does not change the revs.
The LS needle is about 3 turns out and with the pinch test speeds up at idle.
The transition is good from low to max (the 7800 revs).
Blowing into the fuel tank inlet tubing while blocking the muffler pressure tubing would indicate no air leaks.

I have checked the valves and they are ok.
Compression is good.
The HS needle is level with the fuel tank stopper.
Could some one please help me to obtain more revs.
Cheers
CDJ
       Post #: 1

RE: ASP 180 FS will not rev above 7800 - 5/4/2008 9:17:16 AM   
asmund


 

Posts: 1767
Joined: 11/20/2005
From: Floroe, NORWAY
Status: offline 		I have removed both headshims, reset the valve gaps and drilled the outlet of the muffler to 9mm and added a velocitystack to the carb. All these mods will release more power. Also this engine really loves nitro and will respond really well if you feed it some 15%.
Se my post regarding my ASP 180 fs

(in reply to chris de jon)
       Post #: 2

RE: ASP 180 FS will not rev above 7800 - 5/4/2008 9:32:04 AM   
liquid_TR


 

Posts: 389
Joined: 4/8/2007
From: ISTANBUL, TURKEY
Status: offline 		16x8 Prop on a 180 4 stroke??

first, put a bigger load on the engine.
second, try some nitro! At least 5% nitro in the mix, or even better, 10% nitro would get you very nice running characteristics with higher top end.

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LiQuid TR

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       Post #: 3

RE: ASP 180 FS will not rev above 7800 - 5/4/2008 4:27:21 PM   
Flyboy Dave



Posts: 13175
Joined: 3/20/2002
From: San Bernardino County, CA, USA
Status: online 		....I had to remove a head shim from my 1.20 Magnum because it had
low comprssion from new. I also raised the nitro level to 20%, and the
engine came to life. I picked up about 1500 RPM....

....it made a huge difference.

Dropping down in pitch on the prop will increase revs as well.

FBD.

_____________________________

An engineer says.... "That won''t work".
A mechanic says..."Oh yeah, watch this".
"Old Age, and Treachery will overcome youth and skill".
Revver Bro #4.

(in reply to liquid_TR)
       Post #: 4

RE: ASP 180 FS will not rev above 7800 - 5/4/2008 9:30:21 PM   
Edwin


 

Posts: 3129
Joined: 2/8/2002
From: Leander, TX, USA
Status: offline 		Is this engine a recent installation or has it always been in the airframe. I had this exact problem awhile back on a zero with a saito 180. My problem turned out to be too much head pressure. With a 24oz tank sitting about 1" too high I could only get to half throttle before it would die. Changed the tank to a 15oz, same engine, ran fine through the entire throttle range. But a 180 with a 15oz tank is a pretty short flight so I swapped the 180 with a 120. Thats what it flys with now. Tank placement was pretty much fixed, couldnt lower it or move it anyplace else.
Edwin

(in reply to Flyboy Dave)
       Post #: 5

RE: ASP 180 FS will not rev above 7800 - 5/4/2008 10:01:13 PM   
Flyer95


 

Posts: 913
Joined: 9/21/2004
From: STOCKHOLM Akersberga, SWEDEN
Status: offline 		Which Master prop are you running? They have standard master nylon, master classic and wooden props. The classic turns higher rpm and the wooden turns lower with the standard ones somewhere in between.
It seems like your engine is about 1000rpm short of average numbers that I have seen in review and tach.readings for that engine.
On a Saito180 I usually run APC 18x6w/17x8/ or MenzS 18x6 and they all give about 8500rpm +- 200rpm depending on the prop. and weather conditions. My homebrew fuel is 10% nitro "recommended" and 20% oil 50/50 castor/syntetic mix. Been running many gallons of this fuel for a few years now in all my fourstrokes and no engine cleaning have been needed.

(in reply to chris de jon)
       Post #: 6

RE: ASP 180 FS will not rev above 7800 - 5/8/2008 7:09:58 AM   
chris de jon


 

Posts: 38
Joined: 2/2/2003
From: australia, AUSTRALIA
Status: offline 		Hi and thank you for responding.
I did not reply sooner as I had more testing to do.
Asmund:
Your 180fs figures are very impressive.
You said no Nitro gave you 8100 on 18x6 and a Volk 17x4 at 8800
As mentioned in my post I am only able to get 7800 to 8100 on a 16x8 It is a Master Classic with no nitro.
I ran a Volk 17x4 and got no improvement at all.
Could you please let me know the basics of your setup. So that I may compare.

Tank size I have changed from a 20 Oz to a 16 oz in case draw was a problem, and also had no improvement
Fuel I am running 16% cool power and 2% castor
How many turns of the main needle is your motor
My main needle is just over 1 turn out
My LS needle is about 3 turns out.

I have reset the tappets and checked them many times .102mm is tight .
I have now replaced all the O rings in the needle and manifold.

I have blown out the jets with a syringe
A new F series plug did not change anything.
I mixed a new batch of fuel and that also has not altered anything

As mentioned I do not run Nitro as it is hard to get here.

I was under the impression that nitro only improved transition and idle. These are both pretty good. It is top end I am after. Does nitro improve top end?

This is not a new installation it has about 50 flights now and was fine until a week ago when it just sagged off. My model likes the 16x8 and flies well at about 8500 so that 600 or so that I have lost really makes a difference.

I am coming to the opinion that maybe the tolerances on my motor are not as good as yours as nothing seems to improve it.

I would love to know what has caused the change and any more input to try to improve the engine performance would really be appreciated.
Cheers
C de J

(in reply to Flyer95)
       Post #: 7

RE: ASP 180 FS will not rev above 7800 - 5/8/2008 8:20:40 AM   
liquid_TR


 

Posts: 389
Joined: 4/8/2007
From: ISTANBUL, TURKEY
Status: offline 		Of course nitro gives higher power output, when the compression ratio is compensated for..

The side effects are easier to tune engine, much better idle and faster throttle response.

why do you think boat racers use 40 - 60% nitro in their fuels? not for transition

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LiQuid TR

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RE: ASP 180 FS will not rev above 7800 - 5/8/2008 11:14:12 AM   
Flyer95


 

Posts: 913
Joined: 9/21/2004
From: STOCKHOLM Akersberga, SWEDEN
Status: offline
quote:

ORIGINAL: chris de jon


This is not a new installation it has about 50 flights now and was fine until a week ago when it just sagged off. My model likes the 16x8 and flies well at about 8500 so that 600 or so that I have lost really makes a difference.

I am coming to the opinion that maybe the tolerances on my motor are not as good as yours as nothing seems to improve it.

I would love to know what has caused the change and any more input to try to improve the engine performance would really be appreciated.
Cheers
C de J


If your engine used to do 8500rpm on a 16x8 and now only does 7800 on the same prop. then something has happened with it. 8500 on a MA-classic 16x8 is not bad but 7800 is low and makes me think maybe this one is simply worned out or have burned valve seats and leaking valves ? or fuel draw problems? Does it have good compression when turned over by hand? I think ASP recommends a good amount of castor oil in the fuel for these engines.

(in reply to chris de jon)
       Post #: 9

RE: ASP 180 FS will not rev above 7800 - 5/8/2008 1:04:29 PM   
martenson


 

Posts: 284
Joined: 5/14/2006
From: Stockholm, SWEDEN
Status: offline 		Might even be worn or damaged valvesprings, does it sound as it used to?
Pistonring, valve seat, valvesprings this is just some of the thing to check.

Good Luck

(in reply to Flyer95)
       Post #: 10

RE: ASP 180 FS will not rev above 7800 - 5/8/2008 1:41:51 PM   
Edwin


 

Posts: 3129
Joined: 2/8/2002
From: Leander, TX, USA
Status: offline 		Sounds like time for a tear down. I would look for a bunch of carbon buildup around the valve seat and on the valve stem. Carbon cleaning is a high time maintenance proceedure for me. But, I dont think that would produce the kind of symptom you're seeing and 50 flights (or so) shouldnt build up that much carbon. Just my opinion.
Edwin

(in reply to martenson)
       Post #: 11

RE: ASP 180 FS will not rev above 7800 - 5/8/2008 2:34:04 PM   
Sport_Pilot



Posts: 7242
Joined: 1/21/2002
From: Acworth, GA, USA
Status: offline
quote:

It is top end I am after. Does nitro improve top end?


Top fuel dragsters do a quarter mile in less than 5 seconds and 300 MPH. Yeah boy, does nitro improve top end!

(in reply to Edwin)
       Post #: 12

RE: ASP 180 FS will not rev above 7800 - 5/8/2008 2:38:18 PM   
Sport_Pilot



Posts: 7242
Joined: 1/21/2002
From: Acworth, GA, USA
Status: offline
quote:

ORIGINAL: martenson

Might even be worn or damaged valvesprings, does it sound as it used to?
Pistonring, valve seat, valvesprings this is just some of the thing to check.

Good Luck



Another thought, take off the intake manifold and check if it did not suck in some debris. I recall someone finding an insect in there at one time.

(in reply to martenson)
       Post #: 13

RE: ASP 180 FS will not rev above 7800 - 5/9/2008 10:58:16 AM   
martenson


 

Posts: 284
Joined: 5/14/2006
From: Stockholm, SWEDEN
Status: offline 		A topfuel engine on methanol gives circa 3500hp and on nitro over 8000hp.
I know, I'm working on one now

(in reply to Sport_Pilot)
       Post #: 14

RE: ASP 180 FS will not rev above 7800 - 5/9/2008 1:30:34 PM   
Edwin


 

Posts: 3129
Joined: 2/8/2002
From: Leander, TX, USA
Status: offline 		And another thing, I keep a can of carb fixit in a can (wd-40). Sometimes crud gets through the fuel line and jams up in the needle valve area. It doesnt take much. Pull the needle valve out and spray wd-40 th