5.0GL Volvo Penta wont run....

[mikeneal]

I have 1999 VP 5.0GL with ~900 hrs on it and took boat out Wednesday after work and ran fine for while (2 hrs) and when idling for while when switching riders it would hesitant and miss when pulling rider up. (wake board boat). I have put about 18 hs on new iginition stuff (coil and module). Would always clear out and pull strong after 1st hesitation. Once when pulling up rider under load after long idle it popped thru carb once so figured was slightly lean on bottom so fatted the idle screws up. Next rider ran better then after while pulling up rider and ran ~10 minutes). Next rider it missed badly and shut totally off. Fired right back up and revved OK. Started to head to the ramp w/o rider and sat and idles while put stuff away and when tried to leave it shut off, now wouldn't restart, kinda stumbled and acted like ran out of fuel so checked fuel pump and was not running when engine cranked. Jumped the pump @ relay it high current draw and pump didn't run so towed back. Next day after work pump ran, thought it was intermittent pump and replaced it anyhow. (had one fail right after I bought boat 5 yrs ago so figured not totally uncommon for VP pumps to fail). I replaced pump today and still wouldn't run. Has spark, but looks kinda weak. Replaced all plugs thinking maybe they loaded up and still wont run. There is fuel in the carb when pump accelerator pumps so it has fuel now for sure. I even tried some fuel in carb throat thinking maybe float stuck but not even a sputter so all is left is ignition and compression. I took center lead off coil will jump about 1/8"maybe 1/4" and has little yellow in it. Is that too weak to fire under compression???? If you read old posts I recently had ignition module fail and replaced it and coil with MSD Blaster coil. Maybe new module got killed by MSD coil? Maybe i have a bad new module, I bought it online and when it arrived I realized why it was 75 dollars and not 200 as it was after market and potting on underside was not the best.

I am thinking now maybe I will OEM coil and module , plus a cap and rotor for good measure while I messing with it. Hard too believe cap and rotor could shut it off though after basically running fine.

I am supposed to take boat to the Keys in 2 weeks so pressure is on to get it reliable. Any advice is appreciated.

Thanks in advance.

 

[Don S]

Re: 5.0GL Volvo Penta wont run....

Put the proper OEM parts in it.

 

[mikeneal]

Re: 5.0GL Volvo Penta wont run....

I am going to try OEM stuff ASAP, hopefully get them locally and try tomorrow night. Removed port side riser tonight and coil (I have to take riser off to get at coil.) I had no idea my on-line module I bought a month ago was not factory and was really disappointed to see it was not when it arrived. Typically i try to buy OEM stuff. At this point I just need to get it reliable again before TowBoat cancels me.

Put the proper OEM parts in it.

 

[P 0 P E Y E]

Re: 5.0GL Volvo Penta wont run....

Sounds like you know your boat very well and have a good handle on what to look at.

Did you check the fuel for water? Are you sure? We now use a paste to check this post MTBE gas.

What did the spark plugs look like when you changed them? Fuel soaked?

From your post, it really sounds like water in gas.

 

[P 0 P E Y E]

Re: 5.0GL Volvo Penta wont run....

I was too busy typing to see OEM recommendation.

I would agree

 

[Don S]

Re: 5.0GL Volvo Penta wont run....

From your post, it really sounds like water in gas.

It does, up to a point.

I took center lead off coil will jump about 1/8"maybe 1/4" and has little yellow in it. Is that too weak to fire under compression????

It should jump bright blue spark 1/2" with no problem.

 

[mikeneal]

Re: 5.0GL Volvo Penta wont run....

Not even close to 1/2" and has some yellow in it.

One thing that sorta concerned me is I have 12.1V at battery and only about 11.4V @ coil with key on. I know the circuit ha some resistance but not sure how much is acceptable. I cleaned all connections thoroughly and voltage stayed same. It drops to about 9.8V @ coil when cranking but I have second battery and wired the coil to it and gave it solid 12V while cranking and spark looked the same so i guess the ~10V while cranking is OK.
Fingers crossed she runs with new ignition stuff.

It does, up to a point.



It should jump bright blue spark 1/2" with no problem.

 

[mikeneal]

Re: 5.0GL Volvo Penta wont run....

Replaced module, coil, cap and rotor and it fired right up. The old module has some heat discoloration in the potting material and was pulled away from housing so I am betting it was the module. Aftermarket junk I am betting. On the muffs it has a fairly substantial hesitation when you open throttle quickly, runs fine if you don't open it super fast, at leats to the extent I can run it on muffs. I am going to try to adjust idle mixture and check timing tomorrow after work and perhaps water test it. I don't think there is enough slop in the module mounting to alter timing but you never know and easy enough too check it.

 

[mikeneal]

Re: 5.0GL Volvo Penta wont run....

I checked timing and was slightly late so adjusted to toe specs but still had bad hesitation so I ordered the carb rebuild kit and in the meantime put the factory 2 barrel carb back on and sea trialed it last night. Boat ran great for the ~2 hrs I had it on the water.