rubbish engine pump fix
#1
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From: Kwazulu Natal, SOUTH AFRICA
Hi all
Well after having an expert look at my setup (my engine kept going leen and losing power) he told me that the engine was the problem. My question is, will a fuel pump fix this or is it not worth the bother and do I just need a new engine?
Thanks
Gareth
Well after having an expert look at my setup (my engine kept going leen and losing power) he told me that the engine was the problem. My question is, will a fuel pump fix this or is it not worth the bother and do I just need a new engine?
Thanks
Gareth
#7
Gareth,
A simple try would be to run it richer than normal and see.
If you want to know what a pump could do to improve the problem of your engine, install it in a test stand with the biggest tank that you have, or with several small tanks connected in paralell.
Make it work for some time in those conditions and see how it does.
More volume of fuel will keep the level about the same for longer time; hence the pressure of the fuel at the spray bar of the carburetor will be as constant as with a fuel pump.
Best luck!
A simple try would be to run it richer than normal and see.
If you want to know what a pump could do to improve the problem of your engine, install it in a test stand with the biggest tank that you have, or with several small tanks connected in paralell.
Make it work for some time in those conditions and see how it does.
More volume of fuel will keep the level about the same for longer time; hence the pressure of the fuel at the spray bar of the carburetor will be as constant as with a fuel pump.
Best luck!
#8
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From: Kwazulu Natal, SOUTH AFRICA
thanks guys
I thought it was a problem with the fuel supply-only this last weekend after much testing did my friend say that it was the engine that was the problem. The engine goes lean from even a slight climb. I have tried running it rediculously rich but after about 30 seconds in the air back to square one. I guess I need a new engine.
I thought it was a problem with the fuel supply-only this last weekend after much testing did my friend say that it was the engine that was the problem. The engine goes lean from even a slight climb. I have tried running it rediculously rich but after about 30 seconds in the air back to square one. I guess I need a new engine.
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From: Kwazulu Natal, SOUTH AFRICA
It is a master airsrew prop on an OS 40 engine. It is a really simple engine with an air bleed for the slow speed needle. My friend and local guru, Neil Allen spent a whole day checking the system out, even replaced the fuel tank, and could not find anything wrong with the fuel tank, lines or installation. He concluded it must be the engine and I trust him. The engine goes lean very quickly in the air, and is particularly noticeable when climbing. It doesn't matter how rich you start it, the problem will arise.
#12
Sounds like an FP or LA plain bearing engine (with the air bleed carb). What size prop? Are you running muffler pressure to the tank? Is the clunk in the tank clear of the back of the tank? Where is the tank centerline compared to the needlevalve? How far away from the engine is the tank? What size fuel tubing are you using? Is there excessive wear in the plain front bushing that would allow air to be sucked in? When you level off from a climb does the engine run ok or stay running lean. When you start it up do you hold the plane nose high before putting it on the ground to see if the lean condition happens? Your trusted friend should, and hopefully did, check all of these before condeming the engine to the rubbish pile.
Sincerely,
Richard
Sincerely,
Richard
#13

Hi!
An accomplished R/C pilot can see at once if the engine is worn out by just turning the engine over....! Simple as that!!!
It's the piston to cylinder fit that is important. If the it's worn out... just get a new piston/cylinder set!
But if that guy knows anything about engines I assume he has tried a "Uni-flow" tank set-up ...or a Tetrra "Bubbleless tank?
...And get rid of that MA prop! It's the worst prop you can use. Get a RAM or APC !!
An accomplished R/C pilot can see at once if the engine is worn out by just turning the engine over....! Simple as that!!!
It's the piston to cylinder fit that is important. If the it's worn out... just get a new piston/cylinder set!
But if that guy knows anything about engines I assume he has tried a "Uni-flow" tank set-up ...or a Tetrra "Bubbleless tank?
...And get rid of that MA prop! It's the worst prop you can use. Get a RAM or APC !!
#14
All the explained above is great advice, things that you could verify yourself.
I would add: check the nipple of the muffler, where the silicon tube is plugged to, sometimes the little hole is clogged and the tank does not receive proper pressure.
Set ups that are sensitive to non-level positions, normally have problems with low muffler pressure reaching the tank.
Last week I had a similar problem with one engine that had been working well.
It was hard for me to find the problem: a little crack in the silicone tube, just after the muffler nipple, was leaking out the exhaust pressure.
Best luck with the engine.
If you quit on it, just send it to me in Florida!
I would add: check the nipple of the muffler, where the silicon tube is plugged to, sometimes the little hole is clogged and the tank does not receive proper pressure.
Set ups that are sensitive to non-level positions, normally have problems with low muffler pressure reaching the tank.
Last week I had a similar problem with one engine that had been working well.
It was hard for me to find the problem: a little crack in the silicone tube, just after the muffler nipple, was leaking out the exhaust pressure.
Best luck with the engine.
If you quit on it, just send it to me in Florida!





