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carb empties when motor tilted 1981 90 hp

W

weasel

Member
I have a 81 e90tlcim v4, my problem is that the motor dies out at full throttle, can back it down to an idle motor stays running but it is kind of rough. I am pretty sure I have a carb problem, because when the motor is tilted up to the travel position the bottom carb empties out the front. I am thinking maybe a stuck float in the bottom carb. Am I on the right track? thanks in advance.
 
Re: carb empties when motor tilted

I would be more inclined to think fuel pump or a restriction in the fuel system for the dying out at full throttle.

As for the carb dumping out, the airbox is supposed to catch it and feed it back in through the small hose connected to the bottom. It's common for the carbs to dump out to some extent when the motor is fully tilted. If it's leaking outside the airbox, the gasket between the carb and airbox, or the gasket on the bowl may be bad. Make sure the bolts aren't loose. Don't reef them down though, it's only aluminum.
 
Re: carb empties when motor tilted

If the engine dies out when you apply full throttle, that's usually fouled carburetors.

If the engine runs fine at full throttle for awhile....... then dies out, I'd be inclined to think that it was running out of fuel for some reason.
 
Re: carb empties when motor tilted

When I tilt the motor up, the top carb has a few drops leak out, the botttom carb leaks out a couple of shot glasses worth of fuel. (comes out the little brass tubes pointed forward in the carbs)
A couple of weeks ago the motor was ran tilted up as far as it could go will still in the water to get out of a shallow water situation.
I thought myself that it was running out of fuel, but when the motor is acting up the fuel line is still full of fuel, and when extra fuel is given to the motor it kills the engine.
 
Re: carb empties when motor tilted

and when extra fuel is given to the motor it kills the engine.
Click to expand...
If by " extra fuel is given to the motor" you mean if the bulb is pumped. Provided that is just with normal pressure, not squeezing it like a frantic gorilla, then you must have a carb ( the bottom one ?? ) in which the float valve is not controlling the level. Stuck damaged or otherwise defective float or a needle valve not seating. As you suspect!

Dying at full throttle I reckon will be a different issue. Fouled carb or fuel flow problem as Joe suggests.
 
Re: carb empties when motor tilted

if it leaks out a cpl of SHOT GLASSES of fuel,..u gotta little problem...why not clean/rebuild the carbs,killing sev birds w/one....stone!...use new parts/kits.
 
Re: carb empties when motor tilted

Leaking fuel out the carbs is normally too much psi in the fuel bowl I had the same problem early this week the float had a crack in it which had fuel weighing down the float inside the fuel bowl
 
Re: carb empties when motor tilted

could it be possible that the fuel pump diaphram is bad, the pump vaccume sorce could be the cylinders that carb feeds. you said no top end, fuel starving, rough idle. maybe something to check,and also the float level needle and seat. good luck.
 
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