Rusten
04-19-2006, 06:02 PM
Hi all,
On my 2000 Moomba I have the Vortec 350 with the stock Holley Carb (4150 style), Holley P/N 75021-1. I had a minor leak from the accelerator pump and thought it would be a good idea to get it rebuilt, rather than just replace the accelerator pump (see earlier discussions). Boy, was I mistaken.
I brought the carb to a well known local rebuilder. They claimed it would be no problem to restore marine carbs and that they've done many before. I gave them my specs, from Holley (600 CFM, 68 Primaries, 66 Secondaries, 2.5 Power Valve, WHITE Secondary Springs) - they ignored them and even claimed it was a 700cfm, despite Holley confirming it was a 600.
I got the carb back and it ran extremely rich, to the point where it wouldn't get above 3,000 RPM, then the plugs fowled and it quit running after 10 minutes. I double checked timing, etc. The engine ran PERFECT prior to the carb rebuild and nothing changed, yet the carb rebuilders claimed it must be my fault. Only after having their mechanic come out and verify (which I had to pay for), did they take it back.
Second time around, I got the carb back and it still runs very rich.
My question: is there something unique to this *Marine* carburetor that requires a unique metering plate gasket or something that the carb shop is consistently doing wrong because they are treating it like a automotive carb? It seems strange they would rebuild it twice and it would have the same problem both times. Particularly considering it ran absolutely wonderful before the rebuild?
I should mention I checked the float level to be even with the sight threads and even lowered that -- and tried leaning out the idle air-bleed screws (although the problem was in the full-throttle spectrum, not just idle). The choke plate is 100% open too.
Thank you in advance for any suggestions,
Rusten
On my 2000 Moomba I have the Vortec 350 with the stock Holley Carb (4150 style), Holley P/N 75021-1. I had a minor leak from the accelerator pump and thought it would be a good idea to get it rebuilt, rather than just replace the accelerator pump (see earlier discussions). Boy, was I mistaken.
I brought the carb to a well known local rebuilder. They claimed it would be no problem to restore marine carbs and that they've done many before. I gave them my specs, from Holley (600 CFM, 68 Primaries, 66 Secondaries, 2.5 Power Valve, WHITE Secondary Springs) - they ignored them and even claimed it was a 700cfm, despite Holley confirming it was a 600.
I got the carb back and it ran extremely rich, to the point where it wouldn't get above 3,000 RPM, then the plugs fowled and it quit running after 10 minutes. I double checked timing, etc. The engine ran PERFECT prior to the carb rebuild and nothing changed, yet the carb rebuilders claimed it must be my fault. Only after having their mechanic come out and verify (which I had to pay for), did they take it back.
Second time around, I got the carb back and it still runs very rich.
My question: is there something unique to this *Marine* carburetor that requires a unique metering plate gasket or something that the carb shop is consistently doing wrong because they are treating it like a automotive carb? It seems strange they would rebuild it twice and it would have the same problem both times. Particularly considering it ran absolutely wonderful before the rebuild?
I should mention I checked the float level to be even with the sight threads and even lowered that -- and tried leaning out the idle air-bleed screws (although the problem was in the full-throttle spectrum, not just idle). The choke plate is 100% open too.
Thank you in advance for any suggestions,
Rusten