2012 Tahoe Q5I 4.3 Mercruiser with 2 barrel carb

[Gregham]

Took the boat out last weekend, and on Saturday burnt through a full tank of ethanol free gas, and on Sunday the only gas I could get was ethanol gas,I filled up the boat, and put it back in the water my son was running it for about 20 minutes, and it stalled ,and would not restart.When I got it back to the campsite the first thing we tried was a new fuel/water separator filter, but it still would not start, it would turn over, but that was all.The next day we brought the boat homes I uncovered it, and put the muffs on, and it started rite up and ran at 160 degrees for about 20 minutes, so the next day my son to it back to the lake to try it again, and the same scenario sputtered, stalled,and would not restart, so he dropped it at a very reputable shop, but they are saying it will be 3 weeks,I was wondering if some of you other happy boaters can help a happy camper/boater?

 

[alldodge]

Need to start with the basics. Being a 2012 and a 4.3 I'm thinking fuel ijected, but your saying carb.
Happen to have the serial number?

It might be a TKS carb, but in any case when it won't start we need to find out if its fuel or spark that is missing.

Since it starts after sitting for a while it fires right up. Bring a voltmeter with you and when it won;t start see if there is 12V on the + side of the coil

 

[Gregham]

Thanks will try that tomorrow,but it seems we are only having the problem on a load.