2001 Mercruiser 5.0 flucuates then dies

[shumbard]

No Title

 

[shumbard]

No Title

 

[alldodge]

The first pick with them side by side, you cannot see the hole offset. My thought was to be able to see the old and new beside each other so one could pick out which one would have the trouble. Appreciate taking the time, but do understand not wanting to take it back off for a pic. We'll get it next time, happy boating

 

[shumbard]

Went back out on the water today. Did some cruising. Went about 2 miles up the lake to the dam. Stopping a few times to swim in the heat going up and back to a friends houseboat. Took another cruise up another channel and back to houseboat to await a summer storm to pass. Went about 3 miles up the lake to a deep cove for some swimming and relaxing. Forgot my anchor so we occasionally had to start and idle away from shore a couple of times. Went to start and engine would start and die. After a few times of this just wouldn't start like last time. We could smell fuel so we just kept swimming for about an hour. When we got ready to leave I turned it over and it fired right up... fluctuated a little and died. Turned over again and it started and I immediately put it in gear and pushed the throttle wide open... it took off but rpm's danced until up and down until it hit about 2000rpms then it just took off and ran. Coming back to the houseboat I expected it to die when I went back to idle but it did fine. Started and idled back to boat ramp a little later as well. I never get any alarms or anything.

 

[alldodge]

This last time reminds me of vapor lock. Motor is stopped, and heat soaks into the fuel system. The signs are when it does start, the motor chugs a bit, and if you can get it to fire long enough to get in gear, to go full throttle, it chugs a bot as it climbs speed until fuel system is refilled.

Mercs fix is to add a booster pump, but IMO the best fix is to route the fuel return line back to the tank instead of the filter

 

[shumbard]

That is about right. Once it started it surged several times.... 5-8... didn't exactly count, then took off and ran fine.

 

[shumbard]

IMO?

 

[alldodge]

Should be good, to keep down on the vapor lock, let motor idle a good while to cool down, and run the blower a while

 

[shumbard]

Thanks. I will give it a shot this weekend