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 carbon/char have built up to the point that it is impairing the engine?br
Do more air bleeding? Change all fuel hoses? Air getting in?brbr
Below is a list of the things I've done so far to the engine and what happened after the change was made. brbr
ghbrbr
*** br
LOG: 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
-ACTION: Run Compression test on engine. Get 400 psi on both cylinders (engine cold). Engine spec is 330-350psi? brbr
-NEXT: ? help. brbr
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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 carbon/char have built up to the point that it is impairing the engine?br
Do more air bleeding? Change all fuel hoses? Air getting in?brbr
Below is a list of the things I've done so far to the engine and what happened after the change was made. brbr
ghbrbr
*** br
LOG: 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
-ACTION: Run Compression test on engine. Get 400 psi on both cylinders (engine cold). Engine spec is 330-350psi? brbr
-NEXT: ? help. brbr
_______________________________________________
Join Excite! - http://www.excite.com
The most personalized portal on the Web!