Hello all, brbr
I got some unexpected results this saturday when I did a compression test on my MD6A, and am hoping for some opinions and guidance if anyone can help. I was fully expecting one cylinder to be low.brbr
I got 400 psi on BOTH cylinders. As I understand, the spec is 330-350 psi. Maybe that is a minimum passing spec.brbr
Should I go back to the Fuel Pump? Timing? Unable to generate proper pressure?br
Could the char have built up to the point that it is impairing the engine?br
Do more bleeding? Change all hoses?brbr
If you want more detail on what has been done so far in tracking down this problem, I have created a log which is below.brbr
Thanks,
groundhogbrbr
***
Log of previous symptoms, actions, and results: brbr
-Symptom: Engine cutting out like it was out of gas when increasing throttle beyond 15%, eventually leading to it not starting at all for more than a few seconds. Engine sounds like only one cylinder is firing.br
-Action: Clean or change all fuel filters, change electric fuel pump.br
-Result: Engine starts again. Can throttle up slightly more. Black smoke, engine labours, and eventual cut out on any throttle up.brbr
-Event: Marine mechanic I met in the marina tells me that motor seems to be primarily using only one cylinder based on engine sound and uneven heat generation at top of cylinder.br
-Action: Both injectors pulled and rebuilt.br
-Result: Engine no longer cuts out at any speed. Boat speed goes from a dribble before injector rebuild to the speed of a quick walk (3-4 knots?) after rebuild. Boat can now actually produce a small wake. Engine sounds basically the same as beore. Used digital thermometer and the top of one cylinder lags the other by about 10-15 degrees F at start up. At 50% throttle and above, thick black smoke, RPMs or boat speed do not increase. Black charry stuff comes out of exhaust sometimes.brbr
-Event: Run Compression test on engine. Get 400 psi on both cylinders (engine cold). Engine spec is 330-350psi?
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I got some unexpected results this saturday when I did a compression test on my MD6A, and am hoping for some opinions and guidance if anyone can help. I was fully expecting one cylinder to be low.brbr
I got 400 psi on BOTH cylinders. As I understand, the spec is 330-350 psi. Maybe that is a minimum passing spec.brbr
Should I go back to the Fuel Pump? Timing? Unable to generate proper pressure?br
Could the char have built up to the point that it is impairing the engine?br
Do more bleeding? Change all hoses?brbr
If you want more detail on what has been done so far in tracking down this problem, I have created a log which is below.brbr
Thanks,
groundhogbrbr
***
Log of previous symptoms, actions, and results: brbr
-Symptom: Engine cutting out like it was out of gas when increasing throttle beyond 15%, eventually leading to it not starting at all for more than a few seconds. Engine sounds like only one cylinder is firing.br
-Action: Clean or change all fuel filters, change electric fuel pump.br
-Result: Engine starts again. Can throttle up slightly more. Black smoke, engine labours, and eventual cut out on any throttle up.brbr
-Event: Marine mechanic I met in the marina tells me that motor seems to be primarily using only one cylinder based on engine sound and uneven heat generation at top of cylinder.br
-Action: Both injectors pulled and rebuilt.br
-Result: Engine no longer cuts out at any speed. Boat speed goes from a dribble before injector rebuild to the speed of a quick walk (3-4 knots?) after rebuild. Boat can now actually produce a small wake. Engine sounds basically the same as beore. Used digital thermometer and the top of one cylinder lags the other by about 10-15 degrees F at start up. At 50% throttle and above, thick black smoke, RPMs or boat speed do not increase. Black charry stuff comes out of exhaust sometimes.brbr
-Event: Run Compression test on engine. Get 400 psi on both cylinders (engine cold). Engine spec is 330-350psi?
_______________________________________________
Join Excite! - http://www.excite.com
The most personalized portal on the Web!