4.3 mercruiser shut down after about 20 mins

[s2ntburd]

I just bought a 1997 glastron 195 se with 4.3 mercruiser carbureted aplha one out drive. I just had the fuel/water filter, plugs, cap and rotor changed and the first time i took it out for about 2 hours it ran great no problems. Now the second time i went to take it out i was on the water for about 20 mins going full throttle and the motor just shut off. would start for a second and stall back out. i let it sit for about 15 mins and it started back up and i got about 3 mins out of it and it died back out. I had to get towed back in. Any ideas what it could be? The guy at the boat shop said it sounded like the coil but it seems like its getting spark.

 

[Bt Doctur]

clogged fuel sep, sticky anti-syphon valve, is there spark from the coil?

 

[s2ntburd]

Im not 100 percent but i would say there is spark it would start for a second or two and just die out then once i sat dead in the water for 15-20 mins it would start up and run fine for 3-5 mins and die right back out. it ran great 3 days before this and then like i said i was out there for 20 mins or so was going full throttle fine and out of no where it just shut off. No bog down or anything just shut down.

 

[Maclin]

This could be a fuel delivery issue. I believe your engine has an electric fuel pump. Those only get power when the engine is running, thru an oil pressure switch (not sender). There is a bypass that gives it power when cranking, but after the engine starts the power is routed thru the oil pressure switch, this is a safety feature. If the switch fails then the fuel pump will only get juice when the engine is cranking, giving it about 3 minutes worth of above idle fuel in the bowl. The pressure switch will have two wires, not just one like the sender. You can jump those two wires to see if the pump will run.

 

[s2ntburd]

Do you know where that switch is located on the 4.3 merc?

 

[DeepBlue2010]

It is located on the port side of the engine at the end of the engine block(near the transom) and to the bottom. Just above the oil filter if the filter is installed on the bottom of the block not remotely. There are two switches there, one for the alarm and the other is for the fuel pump both installed on a Tee fitting. Your fuel pump switch is the one that has two wires connected to it.

 

[s2ntburd]

It was that oil switch. Thanks for all the help.

 

[Maclin]

Good deal :rockon: