1998 Volvo penta 5.0gipbycce with a dp-sm outdrive. I put the boat in the water last week and it ran ok... I gave it some juice on the way to the marina and it really struggled. I limped to the marina and looked at a few things and noticed that after changing the spark plugs I mixed 2 of the plug wires up and it wasn't firing correctly. I swapped those and took it for another run and it ran like a top... better than last year. Ran good for a couple of days and then I noticed it started to shake quite a bit at idle, both in gear and in neutral. The idle is low... about 425 rpms and it should be up around 600. The shaking isn't as bad above 1000 rpms and at cruise it is almost unnoticeable. Sometimes just idling around the harbor it seems fine... still a low idle, but no vibration. Acceleration seems week and it struggles to get going. Im not really sure how to describe it... except it just doesn't sound right and just doesn't feel right. There isn't a ticking when accelerating but more of a put-put-put... it almost sounds dry. Almost like an exhaust restriction. I have removed the exhausted flaps FYI.
Which brings up the next issue. Yesterday after cruising around I slowed down in the harbor and was going to hook up a fuel pressure gauge. When I throttled back to Idle I watched the temp shoot up to 180 and I shut it down. I waited a while and started it up again. Once it started to creep above 170 I gave it some throttle and it came back down and maintained 170. Sometimes it would start to creep back up and giving it some throttle it would come back down. I checked the fuel pressure which maintained 31psi at the rail. I backed the boat in to the boat slip all in idle and sat there for 10 minutes in neutral... temp never went above 170. Same thing today... it looked like it would start to climb and then I would give it a little gas and it was 0k. I hauled 10 lobster traps and there were only 1 or 2 times that I thought it was starting to creep up... so this is an intermittent problem. Im not sure if it's related to the first problem or not.
Here's what I have done so far... Checked the fuel pressure as stated above. Changed the cap and rotor. changed the fuel filter after 7 hours thinking it may be that. I also just checked the timing. This one has me stumped. I shunt the advance timing and go into base mode at 1000rpms. I set my advance timing light to 8 degrees btdc. When I shine the light on it the timing marks light up like the timing is set right but every 3 or 4 revolutions the engine sputters and the timing doesn't line up... like I said... something is just not right.
I checked the raw water impeller. That was brand new and still looked fine. There are plenty of bubbles and it seems normal (exhaust wise) looking out over the stern... like good water flow as far as I can tell. Manifold and risers are 1 year old and are warm to the touch but I can keep my hand on them. The thermostat housing is hot... 170 degrees I would guess since that is where the sensor is so that makes sense. The water circulation pump failed last year so I replaced that. The hose leading from the thermostat housing to the circulation pump is too hot to keep my hand on and the circulation pump is also too hot for me to hold my hand on.
I should also note that top rpm is 3600. I fought this last year and trouble shot everything imaginable. The boat seemed to run fine and wasn't sluggish. Many suggested that it was the tach and I kind of was leaning that way as everything sounded and ran fine unlike now. I did a compression check last year and all 8 were good. When I find it that will be the next thing I should and will do. I'm just wondering if anyone has any Ideas for now.
Lastly, I've always thought last year that my oil pressure was rather high. The boat sat for 12 years before I got it running last year. I chalked it up to there being some crud build up. This year it seemed normal and actually when I was pulling into the marina it seemed to be a little low... like 35psi.
Sorry for being long winded on this one... just trying to give as much information as possible. Any input is greatly appreciated!
Which brings up the next issue. Yesterday after cruising around I slowed down in the harbor and was going to hook up a fuel pressure gauge. When I throttled back to Idle I watched the temp shoot up to 180 and I shut it down. I waited a while and started it up again. Once it started to creep above 170 I gave it some throttle and it came back down and maintained 170. Sometimes it would start to creep back up and giving it some throttle it would come back down. I checked the fuel pressure which maintained 31psi at the rail. I backed the boat in to the boat slip all in idle and sat there for 10 minutes in neutral... temp never went above 170. Same thing today... it looked like it would start to climb and then I would give it a little gas and it was 0k. I hauled 10 lobster traps and there were only 1 or 2 times that I thought it was starting to creep up... so this is an intermittent problem. Im not sure if it's related to the first problem or not.
Here's what I have done so far... Checked the fuel pressure as stated above. Changed the cap and rotor. changed the fuel filter after 7 hours thinking it may be that. I also just checked the timing. This one has me stumped. I shunt the advance timing and go into base mode at 1000rpms. I set my advance timing light to 8 degrees btdc. When I shine the light on it the timing marks light up like the timing is set right but every 3 or 4 revolutions the engine sputters and the timing doesn't line up... like I said... something is just not right.
I checked the raw water impeller. That was brand new and still looked fine. There are plenty of bubbles and it seems normal (exhaust wise) looking out over the stern... like good water flow as far as I can tell. Manifold and risers are 1 year old and are warm to the touch but I can keep my hand on them. The thermostat housing is hot... 170 degrees I would guess since that is where the sensor is so that makes sense. The water circulation pump failed last year so I replaced that. The hose leading from the thermostat housing to the circulation pump is too hot to keep my hand on and the circulation pump is also too hot for me to hold my hand on.
I should also note that top rpm is 3600. I fought this last year and trouble shot everything imaginable. The boat seemed to run fine and wasn't sluggish. Many suggested that it was the tach and I kind of was leaning that way as everything sounded and ran fine unlike now. I did a compression check last year and all 8 were good. When I find it that will be the next thing I should and will do. I'm just wondering if anyone has any Ideas for now.
Lastly, I've always thought last year that my oil pressure was rather high. The boat sat for 12 years before I got it running last year. I chalked it up to there being some crud build up. This year it seemed normal and actually when I was pulling into the marina it seemed to be a little low... like 35psi.
Sorry for being long winded on this one... just trying to give as much information as possible. Any input is greatly appreciated!