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350 Crusader dies

comogene

Contributing Member
Boat background: Silverton with twin 350 Chevys, not original, but unknown year 350 rebuilt blocks dressed as Crusader. Holly 4-barrel (square bore), closed cooling and Mallory YL distributors with external resisters. Single fuel tank feeds both engines.

Port engine starts and runs fine at all speeds.

Starboard (opposite rotating) starts fine and runs for about 1/2 hour at headway speed while in no-wake zone. Suddenly dies. No hesitation or misses. Just dies. Cranks, but will not restart. 15 minutes later, will restart and run for a period of time.

First time it happened at low speed, changed out Mallory ignition module #609. Headed out and again died in no-wake zone, same as before. Ran on one engine until end of no-wake (15-20 minutes), restarted engine, ran at 3000 to 3500 for 10-15 minutes, then died.

When running, water temp is 170-175 according to the flybridge gauge, oil pressure is normal, around 40 lbs and voltmeter is showing 13-14 volts.

Both water separator and internal carb filter have been checked and cleaned with nothing of any consequence found. Port engine runs from same tank and no issues, so doubt if it is fuel. Inside of distributor cap is clean, no tracks or burn marks and rotor is also clean with evidence of spark transfer. All wires tight and terminals clean.

Any thoughts, suggestions?

Gene
 
Check your coil Gene, sounds like it might have a crack in it that when the engine gets warmed up it quits and takes time to cool off before it will start. You could swap the coils between the two engines and if the problem follows the coil you will know for certain.
 
Thanks for the suggestion concerning the coil. I had a similar thought and ordered a replacement from Mallory just to be on the safe side. I had hopped to test the coil right after it died, but was unable and swapping at that point was impossible due to the layout of the salon and access to the engines. New coil it is and will report back.

Thanks much.

Gene
 
Mark:

Makes absolute sense and that is why I posted to the forum. A lot easier than trying to disconnect the coil sitting on top of the hot manifold. Thanks for the great idea.

Gene
 
My go-to first step in these cases (engine runs and then suddenly doesn't) has always been to put a small puff of starting fluid in the carb. If the engine starts and then dies you know you have a fuel problem. If it does not kick over then you know you have a spark problem. This gives you a path to go down.
 
When that problem engines dies, you need to determine the root cause...like John suggests, its usually spark or fuel...then you need to figure out why the issue arose...it could be a simple as the ballast resistor has aged and is no longer supplying any current to the coil once it get 'hot enough'...
 
Thanks to all. When the engine died and would not restart, my first thought was fuel. I did squirt some fuel while cranking and would not start. Since had air and fuel, knew it had to be spark. Issue then became where? I looked at obvious issues first: cap, rotor, wiring. Then went to module. Now to coil and ballast resistor. Once those are in, we will take it out again with a timing light handy and fingers crossed.

Gene
 
Boat background:

Starboard (opposite rotating) starts fine and runs for about 1/2 hour at headway speed while in no-wake zone. Suddenly dies. No hesitation or misses. Just dies. Any thoughts, suggestions?

Gene
Let it die again, then take a look at your spark plugs. If they're wet, you may be getting water in from riser gasket failure. The water will wet-out the plugs and foul them. If anything, this is a good and easy thing to rule out.
 
Thanks all for your ideas. First changed ignition module, problem persisted. Changed coil; ran for an hour and then died. was able to restart after a while. Finally, pulled ballast resister - three cracks on bottom; replaced. Runs without problem. Knew it had to be in the ignition system that was breaking down when hot, but took a while to find out where. Of course it was the least expensive part.

Gene
 
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