Tidal Chaos
Recruit
- Joined
- Aug 18, 2015
- Messages
- 2
I have a 98 225 ox66 that has been giving me grief since I bought the boat; it has twins and one engine runs like a top and I have only had one problem with the port motor, my starboard on the other hand has been on going, I will list what I have done from reading extensively on this site and others. originally this motor started to reduce rpm's by 300-400 rpm at the higher rpm and ran good in lower rpm and idle. I have replaced thermo's, poppet, plugs (X2), coils, O2, water pump, LP pumps, sent injectors to be cleaned, replaced all filters, racor, fuel, vst, and the small one at the top of the fuel rail, ohm tested the thermo sensor, and it drops as the engine heats up.
after doing all this my engine ran great for one trip; on the second trip it was intermittently dropping rpm on the top end, 800-900 and then it would surge back to normal rpms. next trip after that it would warm up as per normal and drop rpm's as it warmed up; but as I would idle out of the harbor or over to the dock the idle would then run at 1200 rpm and only drop when in gear to 700-800 rpm and now the engine won't go over 4000 rpm on the high end.
I brought the boat home from the coast and started looking under the cowel, I removed the plugs that I had just replaced before the trip and #5 looks new and doesn't look like it has fired once the whole time it was in use (around 8 hrs), I checked for spark and there is none, I changed the coil with one I know is good and still no spark, even over 2000 rpm. Plug is wet and compression is good on this cylinder, it is within 5 lbs of the other cylinders. Motor runs smooth and only smokes excessively on start up and then very little noticeable smoke.
What am I missing, is there another sensor that could be causing the cylinder not to kick in once it is over 2000 rpm. appreciate an info that you can pass along. Thx
after doing all this my engine ran great for one trip; on the second trip it was intermittently dropping rpm on the top end, 800-900 and then it would surge back to normal rpms. next trip after that it would warm up as per normal and drop rpm's as it warmed up; but as I would idle out of the harbor or over to the dock the idle would then run at 1200 rpm and only drop when in gear to 700-800 rpm and now the engine won't go over 4000 rpm on the high end.
I brought the boat home from the coast and started looking under the cowel, I removed the plugs that I had just replaced before the trip and #5 looks new and doesn't look like it has fired once the whole time it was in use (around 8 hrs), I checked for spark and there is none, I changed the coil with one I know is good and still no spark, even over 2000 rpm. Plug is wet and compression is good on this cylinder, it is within 5 lbs of the other cylinders. Motor runs smooth and only smokes excessively on start up and then very little noticeable smoke.
What am I missing, is there another sensor that could be causing the cylinder not to kick in once it is over 2000 rpm. appreciate an info that you can pass along. Thx
