Gastibelza
Recruit
- Joined
- May 12, 2021
- Messages
- 1
Hi,
I have a mercruiser 4.3L V6 1991. Thunderbolt IV and pertronix flame thrower II. It runs with way too much advance but will die when I try to bring it back to 8 degrees on the harmonic balancer with timing light (rotating distributor clockwise). I checked TDC (finger in the hole and checking for compression) and harmonic balancer's mark and they align fine so 8 degrees as stated on engine, at idle (700-750 RPM), should be the proper timing. What I think happens is that the engine floods itself as I turn the distributor. I can get it fairly close, maybe 12-15 degrees before it dies. At that point, the plugs are wet but the engine won't restart unless I wait a bit and put it back with too much advance (15-18 degrees? it's off the marks so just a guess). Engine will rev fine at dock but on the water (propeller engaged) it will bog and lose power at around 3000 RPM. I'm thinking because of improper timing because the closer I can get it to 8 degrees the better it performs. Carburetor is clean (rebuilt) and adjusted to specs so mix should be fine (?). Could it be fuel pressure?
I can take videos or pictures or provide serial numbers/info if it helps diagnose the issue.
Thank you,
Phil
I have a mercruiser 4.3L V6 1991. Thunderbolt IV and pertronix flame thrower II. It runs with way too much advance but will die when I try to bring it back to 8 degrees on the harmonic balancer with timing light (rotating distributor clockwise). I checked TDC (finger in the hole and checking for compression) and harmonic balancer's mark and they align fine so 8 degrees as stated on engine, at idle (700-750 RPM), should be the proper timing. What I think happens is that the engine floods itself as I turn the distributor. I can get it fairly close, maybe 12-15 degrees before it dies. At that point, the plugs are wet but the engine won't restart unless I wait a bit and put it back with too much advance (15-18 degrees? it's off the marks so just a guess). Engine will rev fine at dock but on the water (propeller engaged) it will bog and lose power at around 3000 RPM. I'm thinking because of improper timing because the closer I can get it to 8 degrees the better it performs. Carburetor is clean (rebuilt) and adjusted to specs so mix should be fine (?). Could it be fuel pressure?
I can take videos or pictures or provide serial numbers/info if it helps diagnose the issue.
Thank you,
Phil
