Hello,
I have a 1994 Volvo Penta 5.7GI, this is a TBI motor. I searched all of the stickies and other posts before asking this question. I bought this boat with a blown motor and replaced it with a rapidmarine long block over the winter. Got it running and it idles well, and runs pretty well at low RPM. The boat is in the water in a slip now so im hoping to fix this problem on the water. The problem im having is around 2k rpm it starts to fall on its face, sometimes it will rev up to 2300 or right around there but that is it. If i stay in it the engine will stall sometimes...then start right back up and idle fine. I have a couple of things that I think could be issues, I am going to list them below, any feedback would be appreciated, I know everyone is busy trying to go boating themselves.
1. The old motor had two oil preasure sensors or switches. One towards back of intake mani. and one in side of block right above the oil filter. When i was switching over parts the one on the side broke and I was having a hard time finding an identical replacemetn. I started the motor with one of the sensors (one on back of intake) and the guage works, good oil preasure, but it bounces sometimes. I read somewhere that not have the second oil preasure switch can cause issues.
2. When its running and i unplug the map sensor the performance does not change. This makes me think that maybe its running off factory presets or something, doesnt seem to be in limp mode cuz it does rev a little past 2k. I changed the map sensor and it started to run a little more rich while cold, but didnt change anything else really.
3. I am 80% sure the timing is correcct. I know its supposed to be at 8 degrees btdc. While running with the light on it the mark is right around 8. This engine has two diagnostic plugs on the engine, and ive jumped the two wires on the larger plug before setting the timing. Does anyone have thorough directions on how to set the timing on this, I believe it is different than the EST distributor with the shunt. Don I know you will probably be reading this and you directed me to your stickie last time, but that was for a carb model and i believe it is different because both plugs on my distributor are used and if unplugged i do not believe it will run. .
4. When i purchased the boat it had about 80 gallons of gass, i added stabalizer last fall and topped it off yesterday before putting it in water. It has approximately a 100 gallon tank. The fuel pump on the front of the engine is a bit noisy, i changed the filter before starting it. Should I add a lot of dry gas, stabalizer or octane booster??
5. When starting it yesterday and ran really rich and a bit rough, this cleared up witin about 5 minutes.
Any feedback is appreciated, I really appreciate all you guys do on here for basically free.
Chad
5.
I have a 1994 Volvo Penta 5.7GI, this is a TBI motor. I searched all of the stickies and other posts before asking this question. I bought this boat with a blown motor and replaced it with a rapidmarine long block over the winter. Got it running and it idles well, and runs pretty well at low RPM. The boat is in the water in a slip now so im hoping to fix this problem on the water. The problem im having is around 2k rpm it starts to fall on its face, sometimes it will rev up to 2300 or right around there but that is it. If i stay in it the engine will stall sometimes...then start right back up and idle fine. I have a couple of things that I think could be issues, I am going to list them below, any feedback would be appreciated, I know everyone is busy trying to go boating themselves.
1. The old motor had two oil preasure sensors or switches. One towards back of intake mani. and one in side of block right above the oil filter. When i was switching over parts the one on the side broke and I was having a hard time finding an identical replacemetn. I started the motor with one of the sensors (one on back of intake) and the guage works, good oil preasure, but it bounces sometimes. I read somewhere that not have the second oil preasure switch can cause issues.
2. When its running and i unplug the map sensor the performance does not change. This makes me think that maybe its running off factory presets or something, doesnt seem to be in limp mode cuz it does rev a little past 2k. I changed the map sensor and it started to run a little more rich while cold, but didnt change anything else really.
3. I am 80% sure the timing is correcct. I know its supposed to be at 8 degrees btdc. While running with the light on it the mark is right around 8. This engine has two diagnostic plugs on the engine, and ive jumped the two wires on the larger plug before setting the timing. Does anyone have thorough directions on how to set the timing on this, I believe it is different than the EST distributor with the shunt. Don I know you will probably be reading this and you directed me to your stickie last time, but that was for a carb model and i believe it is different because both plugs on my distributor are used and if unplugged i do not believe it will run. .
4. When i purchased the boat it had about 80 gallons of gass, i added stabalizer last fall and topped it off yesterday before putting it in water. It has approximately a 100 gallon tank. The fuel pump on the front of the engine is a bit noisy, i changed the filter before starting it. Should I add a lot of dry gas, stabalizer or octane booster??
5. When starting it yesterday and ran really rich and a bit rough, this cleared up witin about 5 minutes.
Any feedback is appreciated, I really appreciate all you guys do on here for basically free.
Chad
5.