can not throttle to full power

glvu

Member
I have 1957 mm445 industrial. The engine run fine with full power when I started to scoop some dirt with the bucket. The engine died when I tried to scoop compacted dirt, was push the engine and the hydraulic too hard I guess. Usually when this happen I was low on gas and I would pour a gallon and I would up and running with full power. But this time I cannot get the engine to it full capacity. The engine idles fine just a little weak. When I pull the throttle level to quickly the engine would choke and stop. I also saw some smoke shooting on top of the exhaust manifold when I first start. ( see blue circle)

I upload some pictures of what I think is the the intake manifold and the exhaust manifold. I can feel air coming out between the area where the intake manifold and the exhaust manifold is connected (red circle). Will the air leak cause the engine not achieve full power. I have to hold the choke lever half way for the engine to rev higher.



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if it is an intake leak it could lose power. start it up and at a high idle takea propane torch and hold it around the manifold(just gas, nit lit). if the engine revvs up then you you a intake gasket leaking.
 
(quoted from post at 20:27:50 11/30/15) if it is an intake leak it could lose power. start it up and at a high idle takea propane torch and hold it around the manifold(just gas, nit lit). if the engine revvs up then you you a intake gasket leaking.

Thank RW, let me clarify, I can feel the air coming out between the intake and the exhaust manifold. Also, if this the cause of the low power does anyone have any suggestions on how to unbold the rusted nuts?
 
If you have air you feel around the blue circle you might have bad exhaust gaskets as well. They do sell replacement manifolds if you cant get yours apart.
 
Think that you're barking up the wrong tree. Anything felt at the red circle is just exhaust gas escaping by a bad gasket but has nothing to do with engine performance. The exhaust gas is present there to provide heat to the intake manifold. You're having trouble with fuel delivery. Check for abundant fuel flow out the carburetor drain. If that proves positive, remove the main fuel jet assembly and check for obstruction. You can accomplish both in one step by removing the main jet assembly and after the initial drain of the carburetor, observe the steady flow, then check the assembly for any obstruction.
 
(quoted from post at 06:18:06 12/03/15) Im with curt. The tractor will run fine without an
exauste manifold on it. Check fuel flow.

Thanks guys, will starts with the fuel issue and will post results.
 
If you have an air leak between the intake and exhaust manifolds you do not have intimate contact with them. You can not transfer heat to the intake and you will produce carb ice. I have to replace the manifold on my JS II for just this reason. I've tried resurfacing and gasketing to little avail. Shortly after you apply full power everything goes to pieces. As I earlier posted aviation has dealt with this since day one, it has left a lot of people dead and a lot of aircraft destroyed. 35 years in aviation as mechanic and pilot.
 
Sir,
Having to open the choke is the classic sign of lean intake. I would first clean out the carb and install new gaskets with a needle and seat. Then put a clear tube on the bottom bowl drain. Raise the open tube and see where the fuel level is. That is a ten buck fix and normally fixes the problem.

If the engine pops and backfires; open the high speed needle a quarter turn at a time and see if the problem goes away. I would reset the carb after a clean out anyway.

I had a neighbor with a TO something Massey with the same problem. He had to put in a new manifold gasket. I sprayed some WD-40 like stuff around the intake manifold and found the leak for him. No new gaskets were available anywhere for his manifold so he had to cut one from graphite fiber steam board. I am crazy enough to make dies for MM gaskets, but even I draw the line when it comes to Masseys with Continental engines. After cutting a manifold gasket, he was happy his Massey used a TSX series carb. That meant no bowl gasket cutting. He watched me cut an oddball model 63 Zenith carb gasket. That was FUN. (FUN= Fouled Up Nightmare)

New 206/220 intake and exhaust manifolds are easy to obtain and I personally would spend the seven bucks for two #10A20853 gaskets before spending bigger bucks. If you find that the manifolds are not level; just double up on the gaskets. It is easier than running a fly cutter, or shaper tool, over the manifolds anyway. Normally there is no need to start planing iron. Time kills the gaskets and they just blow out. I have seen the gaskets fail at the intake manifold and allow air in. An intake leak will cause loss of power and hard starting. As stated here; a touch of propane, or WD-40 like stuff, will smooth out the engine when it is sucked in the leak. An exhaust leak just makes noise and will not affect power. If you swap the intake; I recommend you install the updated one and enjoy better intake breathing. The price of a new one is many times less than going over an old one anyway.Fixing brittle manifolds becomes a fool's errand when they shatter. Generally new ones are cheaper than the pain of repair. If you use some moly on installation; the manifolds will normally outlast you anyway.

Happy motoring.
Charlie
 

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