tuandabrainz
Member
Guys,
A few months ago, I decided to swap a mercruiser 165 I6 (chevy 250) with a Chevy 292 I6. After having to make modifications here and there to get it to fit, I finally got the engine to run, got it timed properly, and took the boat to the water for my first actual test drive. I never left the dock, as the motor first started and died out after a few seconds. At the time, I noted that some water was leaking out between the 90 degree exhaust elbow and the intake manifold log. I thought that maybe a small amount of water was somehow getting into the intake manifold through the exhaust and quenching combustion. I took everything apart, sanded the mating surfaces to make sure they were true, put in new exhaust gaskets as well as some high temp RTD, and stopped the leak, but the engine still stalls out. I then thought it was, and it still appears to be a carb problem. There mechanical fuel pump is working, because I have fuel up to the carb intake. If I crack open the fitting, fuel pees out, so I know I have good pressure, if I disconnect the fitting all together and turn the motor over fuel pumps out fine. However, when everything is connected, I get very little fuel out of the jets unless I cycle the throttle agressively. If I pour fuel directly into the carb, or cycle the throttle several times, the engine will start, and even accelerate if I move the throttle forward, but will die out as soon as the fuel I poured into the bowl is out. Now, I am thinking the carb needs a rebuild, but I am not exactly sure why I am not getting fuel out without pumping the throttle. If the jets were clogged, I shouldn't get anything at all, and cycling the throttle shouldn't matter, right? Can it be the fuel pump capacity is too low for this larger motor? Or is my original hunch bad and the carb is the issue? How can I test to be absolutely sure before I go to the trouble of a)getting a new carb b)rebuilding the old one. The thing that is most irritating is just a week before the engine was running fine and now i am about to pull my hair from the roots. Any help or advice you can send my way is greatly appreciated.
Tuandabrainz
A few months ago, I decided to swap a mercruiser 165 I6 (chevy 250) with a Chevy 292 I6. After having to make modifications here and there to get it to fit, I finally got the engine to run, got it timed properly, and took the boat to the water for my first actual test drive. I never left the dock, as the motor first started and died out after a few seconds. At the time, I noted that some water was leaking out between the 90 degree exhaust elbow and the intake manifold log. I thought that maybe a small amount of water was somehow getting into the intake manifold through the exhaust and quenching combustion. I took everything apart, sanded the mating surfaces to make sure they were true, put in new exhaust gaskets as well as some high temp RTD, and stopped the leak, but the engine still stalls out. I then thought it was, and it still appears to be a carb problem. There mechanical fuel pump is working, because I have fuel up to the carb intake. If I crack open the fitting, fuel pees out, so I know I have good pressure, if I disconnect the fitting all together and turn the motor over fuel pumps out fine. However, when everything is connected, I get very little fuel out of the jets unless I cycle the throttle agressively. If I pour fuel directly into the carb, or cycle the throttle several times, the engine will start, and even accelerate if I move the throttle forward, but will die out as soon as the fuel I poured into the bowl is out. Now, I am thinking the carb needs a rebuild, but I am not exactly sure why I am not getting fuel out without pumping the throttle. If the jets were clogged, I shouldn't get anything at all, and cycling the throttle shouldn't matter, right? Can it be the fuel pump capacity is too low for this larger motor? Or is my original hunch bad and the carb is the issue? How can I test to be absolutely sure before I go to the trouble of a)getting a new carb b)rebuilding the old one. The thing that is most irritating is just a week before the engine was running fine and now i am about to pull my hair from the roots. Any help or advice you can send my way is greatly appreciated.
Tuandabrainz
