onewhippedpuppy
Petty Officer 2nd Class
- Joined
- Jun 11, 2012
- Messages
- 163
So, pertinent data up front: 2004 Tahoe Q4, 4.3 MCM Mercruiser, 2 bbl carb, Alpha 1, Thunderbolt V. New to me this year, the only known recent maintenance is new exhaust manifolds, impeller, oil change, and serpentine belt last year. Battery is new this spring.
This is a bit of an interesting issue. The boat starts normally and easily, but will sometimes (not always) die. Dying typically is characterized by sputtering then a drop of RPM with a short bit of dieseling before it quits. Sometimes it is immediately after launching, sometimes after boating for a little while, but always in the first half of an afternoon on the lake. It has happened with the boat both cold and at operating temp, and with the boat both in neutral and while under a load. The issue seems random, as I can't find a common theme. Typically I will attempt multiple restarts, hold it in neutral at higher RPM for a few minutes, and once it will steadily maintain RPM it is fine for the rest of the day. It doesn't coincide with filling the boat up with gas, and I use blue Stabil with every tank. Just as an example, it ran great this Saturday then died on Sunday. After multiple restarts on Sunday it ran great for the rest of the afternoon.
Because it's intermittent I really don't quite know how to troubleshoot, so I'm using this opportunity to do the tune-up that I had planned to do this fall after boating season. Current to-do list is fuel/water separator filter, carb fuel filter, distributor cap and rotor, spark plugs, spark plug wires, and clean the spark arrestor. My only theory is maybe a partially clogged fuel filter or fouled plugs, but I'm really not sure. Any other suggestions?
This is a bit of an interesting issue. The boat starts normally and easily, but will sometimes (not always) die. Dying typically is characterized by sputtering then a drop of RPM with a short bit of dieseling before it quits. Sometimes it is immediately after launching, sometimes after boating for a little while, but always in the first half of an afternoon on the lake. It has happened with the boat both cold and at operating temp, and with the boat both in neutral and while under a load. The issue seems random, as I can't find a common theme. Typically I will attempt multiple restarts, hold it in neutral at higher RPM for a few minutes, and once it will steadily maintain RPM it is fine for the rest of the day. It doesn't coincide with filling the boat up with gas, and I use blue Stabil with every tank. Just as an example, it ran great this Saturday then died on Sunday. After multiple restarts on Sunday it ran great for the rest of the afternoon.
Because it's intermittent I really don't quite know how to troubleshoot, so I'm using this opportunity to do the tune-up that I had planned to do this fall after boating season. Current to-do list is fuel/water separator filter, carb fuel filter, distributor cap and rotor, spark plugs, spark plug wires, and clean the spark arrestor. My only theory is maybe a partially clogged fuel filter or fouled plugs, but I'm really not sure. Any other suggestions?