nicklanigan
Contributing Member
Hi all,
I've been gradually restoring and repairing this motor, which I don't think has had much looking after ever.
My remaining problem is a stall under load, which only occurs occasionally, and only after a warm restart where the engine has been off for a few minutes.
In such a scenario, the engine will start just fine, but as the throttle is opened, the engine will rev up, but then quickly slow and stall out completely. The engine can be restarted, and it will idle fine, but will stall out again as the throttle is opened. If I'm fast enough and back off the throttle, the engine will keep running and return to idle. Most of the time though, the engine dies.
In this situation, I've re-primed with the primer bulb, and managed to get going again.
There is occasionally a slight hesitation as the engine rpm increases in normal use - almost as if the engine has to overcome some hurdle - once beyond the hurdle, all is fine and the problem won't repeat, unless the engine is shut down again for a few minutes.
I've also had two occasions in the last couple of weeks where altering the motor trim seemed to cause problems - once was at full speed - I tweaked the trim and the engine slowed right down, and a second time where I was coming into shallow water and raised the motor to have the prop just under the surface. In the second scenario, the motor stalled and couldn't be restarted in that position (I know it's not a great position for the carbs).
So far, I've replaced all the fuel lines, the primer bulb (with OEM), fuel connectors, filter and water separator, and the fuel pump. (old pump was leaking, so had to go anyway). The tank vent is fine, and I've run off a separate fuel tank as a test - same problem. Plugs are relatively new, compression is all fine. Power pack is also new as old one failed. Fuel is good.
My next fix will be to rebuild the carbs, which would seem to be most logical source of the problem given everything else that has been done.
I guess my other potential problem remains an air leak in the fuel system somewhere, but given the engine runs great, and restarts great, I don't think this is the case.
Any other ideas I should be considering?
Nick.
I've been gradually restoring and repairing this motor, which I don't think has had much looking after ever.
My remaining problem is a stall under load, which only occurs occasionally, and only after a warm restart where the engine has been off for a few minutes.
In such a scenario, the engine will start just fine, but as the throttle is opened, the engine will rev up, but then quickly slow and stall out completely. The engine can be restarted, and it will idle fine, but will stall out again as the throttle is opened. If I'm fast enough and back off the throttle, the engine will keep running and return to idle. Most of the time though, the engine dies.
In this situation, I've re-primed with the primer bulb, and managed to get going again.
There is occasionally a slight hesitation as the engine rpm increases in normal use - almost as if the engine has to overcome some hurdle - once beyond the hurdle, all is fine and the problem won't repeat, unless the engine is shut down again for a few minutes.
I've also had two occasions in the last couple of weeks where altering the motor trim seemed to cause problems - once was at full speed - I tweaked the trim and the engine slowed right down, and a second time where I was coming into shallow water and raised the motor to have the prop just under the surface. In the second scenario, the motor stalled and couldn't be restarted in that position (I know it's not a great position for the carbs).
So far, I've replaced all the fuel lines, the primer bulb (with OEM), fuel connectors, filter and water separator, and the fuel pump. (old pump was leaking, so had to go anyway). The tank vent is fine, and I've run off a separate fuel tank as a test - same problem. Plugs are relatively new, compression is all fine. Power pack is also new as old one failed. Fuel is good.
My next fix will be to rebuild the carbs, which would seem to be most logical source of the problem given everything else that has been done.
I guess my other potential problem remains an air leak in the fuel system somewhere, but given the engine runs great, and restarts great, I don't think this is the case.
Any other ideas I should be considering?
Nick.
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