4.3 GXI-F Volvo Penta cranks but will not start

ShockDiver

Cadet
Joined
Apr 24, 2011
Messages
8
Engine: 4.3 GXi-F – Model 3869306 S/N 4012192075
For past 12 seasons, boat comes out of winterization and cranks right up. Some seasons I do fluids in fall, others in spring but always fill with antifreeze.
This season, changed filters and engine would crank but not turn over. I've done a number of things based on other posts and online research: new battery, changed plugs, changed dist cap/rotor, checked fuses, cleaned carb with some cleaner. I noticed a couple relays (fuel pump, ignition) and they were same amps, so I switched them. Now no crank, and ignition fuse (15a) blew. I switched the relays back and put in new fuse and it cranked right up. Thought I was good until about the fourth time out, cruising at 30mph, the boat just shut down. Could not crank it, got towed back to dock. Next day, cranks, but no turn over. Purchased two new relays, swapped both out and no effect, back to square one. Ready to tow to mechanic but any other suggestions on things to check, I would appreciate it!!
 

alldodge

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Mar 8, 2009
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40,582
You have a loose and/or corrosion issue. Might even be the key switch, but start with the Bat and clean to all shinny metal. With Bat disconnected clean grounds and positive cable connections.

The blown fuse could be a chafed wire
 

QBhoy

Fleet Admiral
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Mar 10, 2016
Messages
8,286
I’d agree with the above. I’d start by looking at the ignition wire from key to the starter relay. If this is shorting or loose, you’ll get exactly what you are. Check behind the dash and at the engine end. Check the main harness plug too. Or anything that is dangling in the bilge that shouldn’t be.
 

ShockDiver

Cadet
Joined
Apr 24, 2011
Messages
8
Update: took the boat to a local shop and once they acquired a cable to read any engine faults they didnt find anything wrong with wiring system. They did replace the d-cap with Volvo brand versus the same sized off-brand I ordered/installed and seems to be running fine at the shop when I picked it up. Real test will be a long ride on the water, I'm not convinced the real problem has been resolved.....stay tuned.
 

ShockDiver

Cadet
Joined
Apr 24, 2011
Messages
8
Update: took the boat to a local shop and once they acquired a cable to read any engine faults they didnt find anything wrong with wiring system. They did replace the d-cap with Volvo brand versus the same sized off-brand I ordered/installed and seems to be running fine at the shop when I picked it up. Real test will be a long ride on the water, I'm not convinced the real problem has been resolved.....stay tuned.
Finally got the boat out on the water. Started right up, docked the boat, shut it off to pull trailer out of the water. Upon trying to start up again, it wouldnt. After a number of failed attempts, I primed the throttle and finally started up. Decided to leave port for short ride to dock. Ride from ramp to dock was fine, no issues, actually got it up at 3/4 throttle, ran fine. I let the boat sit idling for good 30 minutes, no issues. Decided to take it out again for short run, but when I attempted to throttle up, engine choke/bucked hard but never died. Idled back to dock. After 2 hours took it out again, no issues, had it running around 3500 rpm, returned to dock. After another two hours, same thing, ran fine. I'll repeat over the remainder of the holiday, with short runs. The main thing is the starting up, seems I have to prime the engine when I never had to in the past 12 seasons.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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47,306
Crud in the fuel system. How old is the fuel? Replace the fuel filter and inspect the contents of the fuel filter in a clear container
 

alldodge

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Mar 8, 2009
Messages
40,582
These new motors need a scanner to find out what's happening. Diacom software on a laptop can record data while its running then it can be reviewed later
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,286
Undoubtedly a battery and/or main cable(s) connecting issue. The tell tale sign of this on an mpi or gxi engine like this, is when you need to catch it on the throttle when letting go of the key (from cranking position). Start with a new battery. Because the battery will crank these engines…doesn’t mean it’s good and should be ruled out.
 
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