Volvo penta 5.0l wont run with water

[Beeman57]

Hi recently acquired a 1994 volvo penta 5.0fi i/o. Kind of baffled here. So I can get it to start on and of with muffs but requires a lot of throttle to start. Once started sound runs great at rpms above about 2000. If it goes below it runs good for a few seconds than just dies out. I did notice when boat is dry I know, shouldn't start like this, but dry it starts with no throttle and idles perfect for about the 10 seconds I let it do it. Again add water to the equation very hard starting won't idle. At the landing can start it Rev it up for awhile 2-3 minutes try to get into gear but dies out once I get near say 1500 rpm or less. Compression around 115, cold all cylinders.

 

[cptbill]

If it's an FI the the engine is a fuel injected ford base motor, you should probably start with fuel pressures and put a scan tool on it

 

[Beeman57]

If it's an FI the the engine is a fuel injected ford base motor, you should probably start with fuel pressures and put a scan tool on it

Check fuel pressure while trying to start or running? Also what would be the scan tool need for these motors?

 

[Scott Danforth]

Compression around 115, cold all cylinders.

compression on a new motor is 150 psi
compression on a worn motor is 125
motor may not run in the 100-115 range.

double check the compression.

check fuel pressure both in idle and in gear loaded

Rinda is the software for all marine motors. https://www.rinda.com/

 

[Bondo]

Hi recently acquired a 1994 volvo penta 5.0fi i/o. Kind of baffled here. So I can get it to start on and of with muffs but requires a lot of throttle to start. Once started sound runs great at rpms above about 2000. If it goes below it runs good for a few seconds than just dies out. I did notice when boat is dry I know, shouldn't start like this, but dry it starts with no throttle and idles perfect for about the 10 seconds I let it do it. Again add water to the equation very hard starting won't idle. At the landing can start it Rev it up for awhile 2-3 minutes try to get into gear but dies out once I get near say 1500 rpm or less. Compression around 115, cold all cylinders.

Ayuh,..... Welcome Aboard,...... Sounds like fuel to me too,.....

Examine the Contents of the fuel filter, for anything other than fresh clean gasoline,.....
Then throw on a fresh filter, 'n try it,....

 

[Beeman57]

Ayuh,..... Welcome Aboard,...... Sounds like fuel to me too,.....

Examine the Contents of the fuel filter, for anything other than fresh clean gasoline,.....
Then throw on a fresh filter, 'n try it,....

Thanks guys, some how the idea came to my head that maybe I was getting enough juice on my compression testing so I paralleled 3 batteries together instead of just the 1 1000mca battery in the boat. Compression all around 130 with one cylinder lower at about 110.... I'm not to concerned about it at this point old motor lots of hours I presume being a 94'. Hooked up muffs and fires right up now haven't taken it to the landing yet. But fuel still may be playing a part? I do have a little bit of float in rpms at idle and when reving at steady throttle..example 1500rpm I'd say it drops about 100-150rpm off and on not consistent. Also what does anyone think rpm on such a motor should be at idle on muffs it seems to hold 750rpm, and bobble down to 600 hundred every 5 seconds. Was thinking run a can of sea foam through er and its got a half tank of fuel fill it up with some fresh? Any reccomendations?

 

[Scott06]

Thanks guys, some how the idea came to my head that maybe I was getting enough juice on my compression testing so I paralleled 3 batteries together instead of just the 1 1000mca battery in the boat. Compression all around 130 with one cylinder lower at about 110.... I'm not to concerned about it at this point old motor lots of hours I presume being a 94'. Hooked up muffs and fires right up now haven't taken it to the landing yet. But fuel still may be playing a part? I do have a little bit of float in rpms at idle and when reving at steady throttle..example 1500rpm I'd say it drops about 100-150rpm off and on not consistent. Also what does anyone think rpm on such a motor should be at idle on muffs it seems to hold 750rpm, and bobble down to 600 hundred every 5 seconds. Was thinking run a can of sea foam through er and its got a half tank of fuel fill it up with some fresh? Any reccomendations?

Did you check the fuel filter ? That will be a good indication if there is water or debris in the fuel. Also in additon to tests recommended above would check the plugs see what they look like and check cap and rotor. I suspect you need some basic maintenance items Dealt with.

 

[dubs283]

But fuel still may be playing a part?

This is the general (wise) concensus, yes

I do have a little bit of float in rpms at idle and when reving at steady throttle..example 1500rpm I'd say it drops about 100-150rpm off and on not consistent......and bobble down to 600 hundred every 5 seconds. Was thinking run a can of sea foam through er and its got a half tank of fuel fill it up with some fresh? Any reccomendations?

This, again leads one to think fuel supply is a focus point concerning your issue. You can put anything you like in your fuel tank and our opinion, other than adding fresh, good fuel is moot. The above recommendations concerning fuel supply/filters is what you should focus on at this point