mr_velocity

Took a ride yesderday, ran about 2 hours. When I idled into the marine I noticed that the RPMs were at 1500, normally 800 in gear. After about 3 minutes the motor quit. It will restart but will not idle. I ran about 2 hours again today, no problems until I came into the lagoon. Again the idle was high for a few minutes then it would just stall. This morning before making the trip I checked the fuel filters, I run Fram PCS5059M and they were clean with no sign of water. I also replaced the cap and rotor, it was time anyway. Double checked the float level and there is plenty of fuel pressure, almost 8lbs.

The other motor also is idling high now too, although it does not stall.

The motors are 509 cu in with MSD ignition and Holley 1050 dominator carbs. Any idea what I may need to check next? Any chance I got a bad batch of gas? I've been hearing stories that people have been getting bad gas around here but can't confirm it.

mr_velocity

Went back and checked for vacum leaks and didn't find any. The vacum port on the carb has been drilled, tapped and plug so that's not the problem either.

28SS

sounds simular to a problem with mine. It turned out to be weak return springs on the carbs. somtimes they would idle fine then idle high or stall . it just dependend how the springs aligned to return. make sure carb plate is closing completly then set idle screw.

mr_velocity

Thanks, I'll check it out tonight.

blue thunder

FYI - I had one of my 2 month old (10hrs or less) MSD ignitions fail Saturday. What mine did was act like it was in rev limit mode while idling, dropping every other cylinder out. Engine would run but sounded like a hit and miss tractor. It only took a couple minutes to wire in the t-bolt to verify. I am not impressed with the robustness of the MSD so far and would look there if you think vacuum is not an issue.

BT