os37 / muffler probs

[dal]

Hi, I am running a brand new os37 with my old thunder tiger muffler. The engine starts beutifully and runs perfect up until about quarter throttle. Then the the more throttle i apply the worse the engine sounds. The revs wont pick up and it sounds as if it is choking. I lay off the throttle and the engine continues to run fine. It seems to me as if the muffler is not alowing enough pressure through to the fuel tank, therfore the carb isn`t getting enough fuel. Well thats how it seems to me although i dont really know much / anything about model engines. I am also running an inline filter between tank and carb. The carb is set at factory settings now but i have tried most settings until it wont even start in either direction.

Is it possible that the muffler just isnt compatible with the engine. I was running a thunder tiger pro 39. I was told the os37 is actually quite a bit more powerfull than the pro 39.

Has anyone any ideas.

Thanks, Dal

[Fixxxer]

Default settings for the 37 are rich, you need to lean the high speed needle off 1 or 2 clicks at a time and try (thats clockwise). Mine runs about 1 full turn and a couple of clicks out. Each engine is slightly diffrent tho and then there's the diffrent fuels that people use which also contribute. If your unsure then you really need to find a local club, there's bound to be somebody who can help you get it running right.

That said if it's new you really dont want to be leaning it out to quickly as the engine needs time to bed itself in. Find a Club, otherwise it may end making things expensive not to mentin dangerous if your completely new.

[dal]

Default settings for the 37 are rich, you need to lean the high speed needle off 1 or 2 clicks at a time and try (thats clockwise). Mine runs about 1 full turn and a couple of clicks out. Each engine is slightly diffrent tho and then there's the diffrent fuels that people use which also contribute. If your unsure then you really need to find a local club, there's bound to be somebody who can help you get it running right.

Thanks Fixxxer, i`ll give it a go!!

[dal]

Default settings for the 37 are rich, you need to lean the high speed needle off 1 or 2 clicks at a time and try (thats clockwise). Mine runs about 1 full turn and a couple of clicks out. Each engine is slightly diffrent tho and then there's the diffrent fuels that people use which also contribute. If your unsure then you really need to find a local club, there's bound to be somebody who can help you get it running right.

That said if it's new you really dont want to be leaning it out to quickly as the engine needs time to bed itself in. Find a Club, otherwise it may end making things expensive not to mentin dangerous if your completely new.

That was the problem. The shop told me to run it at about 2.5 turns out which i was doing, i was then adjusting it in to about 1.5 turns in max which didnt make any difference. I was very paranoid about it going to lean,But it seems the engine wont get up to speed unless it is basically the same as yours, ie. 1turn and 2 clicks out. Any richer than that and it starts hesitating and choking itself.

I dont know what i would do without the people on this forum. Thanks again. Dal

[ARD]

Don't go leaning the engine out until you've had at least three tanks of fuel through it on idle, the break in process is important and will make your engine last a lot longer and work a lot better