Got another OS .18, Put er in the FF and heat cycled it for quite a few tanks. No problems

That was about 2 weeks ago and I got it out today and started it up.
I started her up with no problems and just ran it around slowly to warm up and check temps and it was about 220 and had Tons of blue smoke and no power when i throttled it. So I leaned it out a fair bit and let it run again and it would do a serious bog at half throttle. It seemed to have a nice smoke trail so i checked temps and it was 240. So I leaned it out just a wee bit and the bog got worse. Then I was like ... uh ok, So I richened it up and it actually reduced the bog but with massive smoke trail and not even near the power it should have.

It seems to Idle fine and it doesnt bog off the line. Then it stalled and I wasnt able to restart it. I tried new plugs and everything, glow ignitors are fresh and I tried 3 different ones before giving up for the day. fuel tank was full of good fresh fuel.

So basically, it has a bad bog and its running at 220 - 240 but if I lean it out it bogs worse and if i richen it it doesnt bog but has no power and tons of smoke. And I can't restart it hot.

I'm kinda thinking vapor lock but i have the line away from the cooling head as much as I can with the OFNA tank and the fuel line measure 90 degrees F.

any clues anyone???

Thanks

its always a nightmare when this kinda thing happens.

first off - check under the hsn for any sticky fuel residue. thats the only thing my OS has had tuning issues with, especially after being left for a while.

what fuel are u using out of interest, what nitro and oil content? i ran byrons 25% race stuff thru mine for run in and after. it took a lot more tanks than i was expecting for it to run in fully, but that could be my technique, but... mine ran just as u described for quite a while when running in, was about a gallon of fuel before i got full power from it, and even then it was an accident... "i wonder if itll take any more leaning... bloody hell!!!".

uve probably tried most or all of the stuff below, but thats what i would try...

1 check the carb is spotless under screws etc.
2 check or replace fuel lines
3 swap the tank for a known good one if possible and try that
4 what plug do u have? try an OS#8 in there if u didnt already (should have been suggestion #1)
other than those regular checks... erm... is there another temp gun u can try? i never trust instruments or gauges much!

im guessing the compression is still good in the OS? i hope so!

my sh motor is sulking at the mo, so let us know how u get on please mate

Other than what PJ said:
Firstly how many tanks is "a few" because you should only be leaning it slightly now after each tank, and thats if you have put at least 5 or 6 through it, not leaning it out a fair bit as you describe.

I would richen it up a little on the HSN a little, make sure the LSN is flush, (check needles arent blocked, fuel lines etc) if it starts run a couple more tanks at these settings, then lean it out 1/8th of a turn every tank from there,.. good luck

I had a similar problem with my first os 18... turned out it was a clog in the carb... had to take apart the needle assembly and blow it out.. had the same type of headaches trying to tune.. happened all at once.. ran great and then the problem.... My 2nd os runs great after a lengthy break in.. about 7-8 tanks until almost fully leaned out.. still have a bit to go..

I think I have about 10 tanks in it so far. I am using HPI Power fuel 20% The nearest good hobby shop to me is about 250 kms but there is a crappy one about 100 kms away and thats the only fuel they carry. I have been using OS #8 plugs. I haven't pulled the HSN out of the carb to check for seating though, didn't think of it actually... I checked my fuel lines and tank and they seal well, as does the exhaust and carb.

I will definately pull that needle tonight and take a look see and maybe clean it out a bit. And if that doesnt do it, I guess I'll keep running tanks of fuel through it.

It just seems weird though, this is my second OS .18 CVRX and my first one had tons of power at about 5 tanks and it was still waay over rich.

Thanks for the quick replys and good suggestions guys [sm=thumbup.gif]

EDIT: BTW, can you guys tell me what your OS's HSN and LSN are set at approx. Yeah I know it varies a lot due to many factors, but maybe my first one was an oddball that will be tuned quite differently than this one. You never know.
Thanks again!

Well, I finally pulled the HSN and LSN and the needles are fine and the seats are clean. I guess I'll just have to keep running tanks through it.

Anybody mind posting the settings they use in their OS 18 cvrx's?

Thanks

lsn screw on mine is flush with the surround, hsn... hang on... ill look... worryingly its only 1.5 turns out.

i havent run mine since last summer tho, it may have had a strip down since i cant remember now... i seem to remember 2+ turns was the norm - see what others say first mate.

LSN flush, HSN 2 1/8th turns out.

lsn flush... hsn 2 turns out... I checked the new and the older motor and they were both the same.

Took her out tonight and ran through 3 more 125 cc tanks just on the pavement outside. It seemed to Finally start to smarten up. So I started leaning it out starting from2.5 turns out. I kept leaning it and it started getting quite a bit better. I kept going until it felt right, which ended up being 1 3/4 turns out... I ran it almot WOT a few times about a block's length and it had pretty decent power, not doing any wheelies or anything though. I checked temps and it never got above 240 with the body off. My HSN doesnt look bent or anything but maybe I'll have to take it out and compare it to my other OS HSN to see if it's shorter or something...
Tuned my LSN in and it needed about 1/2 turn in from flush.
It seems to be running ok now, guess it needed a bit more fuel through it. I don't know why it took about 15 tanks to break in but it seems to be ok now.

Dr. Honda has my front diff so I just have an empty case on the front now and man is this thing hard ton control with only 2 wheel braking. And when it goes sideways, the bowtie tires like to grab onto the pavement and flip it over [X(]

What kind of temps are you guys seeing with these engines. I think my other one runs about 250 - 260 at 2 turns out. Whereas this is running about 240 at 1 3/4 turns out.

Thanks all!!!

with the body on and the settings that i posted I was running around 275 - 285 in the grass with the stock tires... It had good power and would pull wheelies if traction was good... didn't get to the track with the new motor so I don't know the temp.. probably lower.. I don't tend to run on asphalt because of the high risk of damage from a rollover..

Hey again!
I know a lot of you run the OS 18s so I just thought I'd let you know what happened with this one.

It was running ok for a while and I just kept running fuel through it and left it a bit rich but not overly. Then after about 4 more tanks, it started having the same issues as before. It would be running too lean so I'd richen it up. Then it would be leaner yet, then Id richen it another 1/8 turn and it would flood itself etc. etc. etc.
To say the least, it was being very uh.. erratic

So I was trying to get it started once when i ran a tank out of fuel, and I was priming the fuel lines and when I let the pull cord go in, I could hear air escaping and the fuel would go back and fourth as i pulled, intead of just forward. Before I could locate the air leak, It fixed itself and started priming fine. Then I was just like [sm=confused.gif] uh....?
So I ran it again and as soon as it leaned itself out for no reason I stopped it and searched for the air leak again. Turned out to be the piece that the carb holding nut screws on to. The nut was tight, but the other side of it, across form the nut, leaked air a bit like it was a slightly loose fit or something. So that was my problem! Sometimes it fit fine and sometimes it would leak. [:@]

I put some hi temp gasket maker on it and let it dry and now it runs fine!

glad you sorted it out... you'll love the engine when everything is running right.

Well, yeah. This is my second one of the same engine. I love the first one. But I have never been more frustrated with anything like this before lol.

hey again...

This engine has got to have something seriously wrong with it. It seemed to be working ok, but never had the power I expected

But now it is having issues again (doesnt seem to be an air leak) and i cannot get it to restart when its hot. By hot I mean above 220 F. It doesnt seem to have much compression when its hot either, which would indicate to me a dead engine. When I am pulling it, when i realease the pull cord I can hear something of a shhhhh type noise but i cannot seem to figure out where it is.

But how could that be? It has less than 1 gallon through it. I know that one time when i was figureing out the air leak issue, it did get up to about 300 for a few seconds, but other than that i have kept it a bit richer than optimal.

What else could cause it to not restart when its hot other than it being dead...?