Old Os 21 running issues

[jclifford]

I have resurfaced by 30 year old Vanning with an OS 21. Got it started finally. Idles well, When I open it up it will run for 30-60 seconds and then just die. It is running slightly rich. I forgot to put the infrared temp gauge in my pocket, ran back into the house to get it and ran back out. Temp was in the 140 degrees F range. I didn't get a chance to check it again. I suspect running temps will be in the 180-200 degree range.
Why is it dying?

 

[cbaker65]

I have resurfaced by 30 year old Vanning with an OS 21. Got it started finally. Idles well, When I open it up it will run for 30-60 seconds and then just die. It is running slightly rich. I forgot to put the infrared temp gauge in my pocket, ran back into the house to get it and ran back out. Temp was in the 140 degrees F range. I didn't get a chance to check it again. I suspect running temps will be in the 180-200 degree range.
Why is it dying?

Low needle maybe too rich causing flame out ,when at idle,the engine is loading up an not clearing out on throttling to full!

 

[jclifford]

it makes the transition from idle to full throttle, runs for 30 seconds, then stalls. is this still the low speed needle?

Thank you..

 

[olds97_lss]

What OS is it? The 21RG? How's it's compression? With the glow plug out, do you feel any pinch when you rotate the crank when it's cold?

I've had quite a few 21RG's over the years. They only got weird when the pinch was way gone (10+ gallons). They would flame out for no reason and be very hard to start when hot.

What plug and fuel are you running?

 

[jclifford]

i do not remember letters after the number 21, this is probably late 80's. I don't remember it having letters.
the engine has probably had 2-3 gallons of fuel through it
No problem at all re-starting after it stalls.
compression feels good, I can turn the flywheel with a reasonable "pop".
running 20% nitro, LHS blend.
the glow plug is probably 30 years old also, but I have pulled it out and it gives me a bright glow. I tried another plug with the exact same scenario so I doubt that is the issue.
I was sort of heading toward it running too rich, I don't know what temp the engine should run at.

 

[cbaker65]

What OS is it? The 21RG? How's it's compression? With the glow plug out, do you feel any pinch when you rotate the crank when it's cold?

I've had quite a few 21RG's over the years. They only got weird when the pinch was way gone (10+ gallons). They would flame out for no reason and be very hard to start when hot.

What plug and fuel are you running?

I was going to say that too ,after they warm up an flame out ,is a indication that it has lost its pinch!...Good call!..

 

[jclifford]

seems to be a consensus, I will check it,

thank you very much!

 

[cbaker65]

seems to be a consensus, I will check it,

thank you very much!

I wouldnt draw the conclusion that it is worn out ,there is other factors!

The temps where your at.
% of fuel & what fuel your using.
Is there any air leaks in the fuel system ,tank ,fuel lines ,carb.
The tune. Running too rich can cause a flame out when you stab the throttle.
Running too lean on the top end could cause it to die as well.

If there is a lot of oil coming out of the exhaust & a lot of smoke ,then it is too rich!
You said it is old engine ,then the O-rings on the needles are probably rotted causing flooded conditions!

 

[jclifford]

I wouldnt draw the conclusion that it is worn out ,there is other factors!

The temps where your at.
% of fuel & what fuel your using.
Is there any air leaks in the fuel system ,tank ,fuel lines ,carb.
The tune. Running too rich can cause a flame out when you stab the throttle.
Running too lean on the top end could cause it to die as well.

If there is a lot of oil coming out of the exhaust & a lot of smoke ,then it is too rich!
You said it is old engine ,then the O-rings on the needles are probably rotted causing flooded conditions!

got it,
I will take the temp immediately after it stalls. 4 minutes after it was 140 F.
I was assuming the temp should be about 200 F, is that correct?

using 20% nitro, from the LHS, runs other engines without issues.

it makes the transition from idle to full throttle without a problem, then runs for about 45 seconds and dies.

I did completely close the needle valve and blew into the inlet, it was totally blocked. It did not seem like there was a leak.

 

[cbaker65]

got it,
I will take the temp immediately after it stalls. 4 minutes after it was 140 F.
I was assuming the temp should be about 200 F, is that correct?

using 20% nitro, from the LHS, runs other engines without issues.

it makes the transition from idle to full throttle without a problem, then runs for about 45 seconds and dies.

I did completely close the needle valve and blew into the inlet, it was totally blocked. It did not seem like there was a leak.

Yea ,most engines like 200 & 220ish ,also ,with 20% nitro ,maybe take the shim out of the head if know one has
done it yet!

If it runs kind of sluggish to get at top end speed ,then it maybe too rich with 20% nitro ,could be a combination!

 

[jclifford]

Yea ,most engines like 200 & 220ish ,also ,with 20% nitro ,maybe take the shim out of the head if know one has
done it yet!

If it runs kind of sluggish to get at top end speed ,then it maybe too rich with 20% nitro ,could be a combination!

that is how I would describe it, hesitates just a touch then goes to full speed.

Is the shim original equipment? if so, I would not have removed it.

 

[cbaker65]

that is how I would describe it, hesitates just a touch then goes to full speed.

Is the shim original equipment? if so, I would not have removed it.

People remove the shim while running 20% nitro ,an keep the shim in for 30% nitro!
However ,should run ok either way ,I would just lean the HSN a little ,like 1/8 turn until the engine
starts to run better ,always keep record of where the needles were!

 

[cbaker65]

 

[olds97_lss]

You kind of always need a shim, it seals the button/head to the sleeve. People add extra shims when increasing to 30%, but even with less nitro, there should still be at least one for sealing purposes and proper compression ratio.

Does sound like it may just be rich. 140F is cold... unless it's 20F outside.

 

[jclifford]

after all was said and done... I leaned it out about another 1/2 turn and it is running continuously! Reasonably nice throttle response. I will lean it out a little further, still running under 200F.

many thanks to all.

 

[olds97_lss]

Glad you got it sorted out! I had thought you adjusted the needles to extremes and it had little effect. Must have been confusing my threads.

 

[doutrnz]

after all was said and done... I leaned it out about another 1/2 turn and it is running continuously! Reasonably nice throttle response. I will lean it out a little further, still running under 200F.

many thanks to all.

Be sure to check out the video cbaker65 linked. I too have watched it before.
Since watching it, I've been able to tune all my Nitros with ease! (Well, a lot quicker than before going through 3/4th of a tank just tuning...) JQ has a bit of an attitude but he is a straight shooter. He tell you how it is. He doesn't sugar coat anything.

 

[monstertruckier15]

1/2 half turn from stock setting is not good on the high needle. You may want to use fuel with more oil lube. (Os recommends 18%) which may be one of your problem to why you leaned out the high that much. And use a fuel filter.

 

[jclifford]

1/2 half turn from stock setting is not good on the high needle. You may want to use fuel with more oil lube. (Os recommends 18%) which may be one of your problem to why you leaned out the high that much. And use a fuel filter.

I don't know where the setting started in relation to stock setting. I am using a LHS fuel blend specifically for cars, I am guessing the oil was at 20%.
thank you for your input. I haven't run too much lately, it is 16 degrees F outside right now!

 

[monstertruckier15]

Fuel blend special for car is junk for old Os engines. It has less % oil around 12% Os recommends 18%