Need advise badly
 

I have an OS 91 FX that I can not get to idle. It will not run below 3000 rpm. I'm running Cool Power 15%, OS #8 plug and several different size props. I've tried everything a buddy of mine and I know to try. Anyone know any secrets on this motor?
thanks, Tom

RE: Need advise badly
 

Tom:

Almost without question you have an air leak. Smear "BlueGlue" over all joints, around the base of the carb, and on the carb retaining screws. It will lookugly, but you aren't going to leave it.

Set the idle, then while the engine is running carefully pull the BlueGlue off a bit at a time. When the engine acts up again you've found the leak.

Bill.

RE: Need advise badly
 

That makes sense Bill. Is there a brand name for the blue glue or is that it?
thanks, Tom

RE: Need advise badly
 

Possibly you will know it as "Silicone Seal" or "RTV." Blue is just the most common color, it also comes in red, black, and clear. Many different brands, Permatex, VersaChem, and GE all make their own versions.

Bill.

RE: Need advise badly
 

OK thanks. I'm off to Ace!

RE: Need advise badly
 

Now it will idle down to 2400ish as long as I leave the glow ignitor on. if I let it idle there for a min or 2 then go to full throttle it dies immediatly like it's lean. I have an OS #8 in it, could the plug be too cold or is it still the mixture?

RE: Need advise badly
 

Tom:

What fuel and what prop? They will affect the idle also.

Bill.

>>Edit: And how old is your fuel? wr.

RE: Need advise badly
 

Cool Power 15% and APC 14/6 pattern

RE: Need advise badly
 

Tom:

A 14x6 prop would be OK on a four stroke, but it seems awfully light for a 91 2s engine. If you have a 15" or 16" to stick on it give that a try. The 14" just might not be enough flywheel for it. The 15% fuel should be OK if it's fresh.

Also, stick a hotter plug in it.

Now if you meant a 91 FS the 14x6 would be a good size for it, I'd say check the valve lash and give it a new "F" plug.

Bill.

RE: Need advise badly
 

The fuel should be fresh, I have a hotter plug to try but not a bigger prop. I can buy one tomorrow but will try the hotter plug first. I may have ground clearance issues with a 15" prop though.
thanks Bill
Tom

RE: Need advise badly
 

The A3 plug made it much better. I got it to idle at about 22-2300ish and then go to full throttle. Is there a slightly hotter plug than the A3 or will it gradually get better?
thanks again,
Tom

RE: Need advise badly
 

Tom:

The A3 is about it. I like the K&B 1L plug, but it's about the same as the OS A3.

Yes, as the engine gets more time on it the idle will get better.

If you can't clear the tips of a larger prop you might try a MAS 14x6 three blade on it. APC has some 3b props also, but I don't know the sizes.

Bill.

RE: Need advise badly
 

thanks Bill

RE: Need advise badly
 

If you can find 'em somewhere.... try the Rossi plugs. They are excellent plugs, and they range from an R1 to an R8... The R1's for engines .10 and smaller, up to the R8's for hot engines turning 20,000+...
If you can't find the right plug in that range... then start looking elsewhere...