Strange Issue w/Volvo 5.7L cutting out

R

rwilhite

Member
Joined
Feb 19, 2001
RO Number
3478
Messages
155
Fine spring day in Titusville, Florida yesterday so the Admiral and I took our 1994 Excel 26SE out on the Indian River Lagoon for an afternoon of boating. Ran into a issue that has me very puzzled.

This boat has a Volvo DPS stern drive with a Volvo GL 5.7L V-8 and a Holley 700 cfm double-pumper carb that was rebuilt by my local boat repair facility (in the past they have been very, very competent) six months ago. The fuel tank was bone dry empty (just replaced fuel gauge sending unit so I know it was dry) and I put in 36 gallons of non-ethanol 89 octane gas.

Engine started up cold perfectly, I idle out of the marina (about 15 minutes) at 1200 rpm, give her the gas and she comes up on plane with no problem. Ran it about 20 minutes at 3600-3800 rpm and everything seems to be working great. I come down off plane and am idling along at 1200 rpm when the engine just flat quits running - no noises or warnings. Check temp gauge and it tells me 150 degrees. Tried starting and it cranks fine but won't start. Give her two full strokes of throttle and again try restart with no luck. I let her sit for ten minutes and she starts right up, running smooth as silk. Again, I put her in gear and am at 1600 rpm and after ten minutes she again just quits running. Try an immediate restart with no luck. After another ten minutes she again starts right up. This time I bring her up on plane and run at 3800 rpm for 45 minutes with absolutely no problems, but when I come down off plane and am running 1400 rpm for about 6 to 10 minutes, she again just quits.

This engine had a complete tune-up (rotor cap, rotor button, timing, plugs and wires) and the repair facility replaced the coil at the same time as they said I had the wrong coil. All that was around ten hours ago (six months) and the last time I had her out she ran perfectly.

I am thinking there is an issue with the low-speed circuit in the Holley carb. The ignition and cranking circuits all seem to me to be working well and the only thing I can come up with to explain why it runs so well at higher rpm and just cuts out at lower rpms is that carb. Maybe something wasn't done right in the carb rebuild?

Any and all ideas, thoughts or suggestions are greatly appreciated.
 
probably electrical but to ck the carb when it shuts down look inside the carb while pumping the throttle if you see gas look elsewhere, if you dont see gas ck the filter and fuel pump. For electrical open and reseal all connectors including battery cables and ground.
 
Carb could be a suspect.. One long shot to check though.. Do you have good voltage at idle to the fuel pump? Had a fellow RO years ago have a similar issue and it turned out to be related to low voltage to the pump at idle which starved the carb after a period of time running at low RPM's.

John
 
My thoughts are as Brucies.

Actually sounds like an internal coil problem or bad connection like Bruce says.
 
Most often if an engine just cuts right off, it's due to an electrical issue. But ...?

If it has an electric fuel pump, can you hear it pump for a few seconds when the ign. switch is turned to just ON when it won't start?

When it will not fire, take the flame arrestor off the carb, and sniff its intake, is it gassy? How about when you hold the choke open and push the throttle lever forward, can you see a jet of fuel and does it smell good and gassy then? If it smells gassy there before you pump the throttle, try starting with throttle at full position.

Do you by any chance have an inductive timing light you can clip on the plug wires to easily see if plugs are firing to some degree, when cranking but not starting? (Or a spare plug you can plug into a cable plug boot and ground against the block...)

You could rule out the vent by checking to see if it stays running with the fill cap off in calm seas, but if a vent or filter restriction it would have to be a bit of a coincidence the cut-out occurs near the same rpm. But it's a remote possibility a sticky ASV could be causing problems.

When running at around the cut-out speed is the boat attitude noticeably bow-higher? If so you might check for too low or too high (aeration) crankcase oil levels causing the low-oil pressure alarm switch to cut-out ignition. If levels are good and you're confident it's the correct dipstick and oil pressure on the gauge has only seemed normal right before the problem, you might disconnect the oil pressure alarm switch on the engine ( not the gauge sender) and insulate that/those wire connector(s) from shorting to ground and see if the engine stays running ( erratically bad switch or it's wire(s) shorting out the ign.? ) You mentioned engine water temp was OK on the gauge, but on I/O's I believe the drive temp is sometimes also included in the alarm & ign. cutout circuit.

I would double check the wires to the coil and the coil secondary to distributor cable to confirm they are all tight and not corroded , check/wiggle connections to any electric fuel pump and its relay an any associated fuse/fuse holder. I'd inspect the inside of the distributor and cap for anything amiss. When it's running again , I'd feel the coil to see if it's getting overly hot (maybe this is the wrong one, not the old one?) Is there a ballast resistor in the circuit?

Sorry I'm not familiar with the Holleys.
 
Before inspecting various devices, determine if the problem is electrical or fuel?
a. Install $15 plug tester (or timing light). Is it firing?
b. Remove air filter, open choke plate, and observe if fuel is injected into the throat when throttle activated. Does it have fuel?
Report findings for next step.
 
Does the Distributor have a Vacuum Advance? Doubt it, but if it does, the pickup plate turns with changing advance and it's possible a wire has flexed to the point of failure. Long shot, but I saw it in older cars. There was a special wire to replace those, designed for constant flexing.
 
I would look at fuel delivery (vent?) first as BillK suggested. Could hook up a separate portable tank and see if problem stops.

Also check the check valve - if new, make sure it is not defective. If original, make sure it is clean.
 
j-d - I don't believe any real marine distributors employ vacuum advance.
 
Heh! Yeah! Ya gotta have all white hair to remember[:P]
 
Thanks for all the helpful replies - as always this forum has a huge store of knowledge and experience.

Ummm, no vacuum advance on this distributor - all electronic and it has a mechanical, centrifugal advance plate and weights.

Gas tank vent is free of all obstructions and I can blow air from the outboard vent into the gas tank with no restriction, so I don't think that is the problem. Besides, it seems to me that if it were a vent blockage the engine would also cut off at higher rpm, and a lot more often that at idle.

Have not had the boat back in the water to look at whether gas is squirting into the carb throats when it stalls, but will definitely check that out.

I will also make sure the coil wires are all tight and seated correctly into the coil and distributor.

If those two things check out, it looks like the issue is narrowed down to the coil.
 
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