94 Mercruiser 4.3L v6 intermidtant shut-down

[larr630]

Hi to all! Have an issue that pops up sporadically. I have a 94 Mercruiser 4.3L v6. It has a new oil pressure sending unit as well as the safety switch that cuts the fuel pump off when oil pressure gets to low. Motor has a new carb, new exhaust manifilds and risers. It also has a new water temp switch and new water temp sending unit. Two things are happening- the port side manifold and riser is getting hotter than the starboard side. And the motor will just shut down like its running out of fuel out of the blue. I replaced the oil pressure safety switch again and then it ran fine. A day later, did the same thing. Seems the electric fuel pump is just shutting down. Could it be a bad fuel pump? Why are the risers at different temps? The bellows exhaust hose split in two and the exhaust mainly comes out of the bellows right now. I put a new exhaust tube on a month ago, but it split in two. Not sure why. I have to replace that tube again, but I figured it wouldnt hurt anything running wise. Unless the motor requires the backpressure from the exhaust to properly cool itself. Any advise would be greatly appreciated..........Larry

 

[Don S]

Re: 94 Mercruiser 4.3L v6 intermidtant shut-down

I replaced the oil pressure safety switch again and then it ran fine. A day later, did the same thing. Seems the electric fuel pump is just shutting down. Could it be a bad fuel pump?

Were the terminal on the switch tight and not rusty? I would be looking for a wiring problem before a failing pump.

Why are the risers at different temps?

Normal at low rpm or on muffs.

The bellows exhaust hose split in two and the exhaust mainly comes out of the bellows right now. I put a new exhaust tube on a month ago, but it split in two.

You didn't put a clamp on the aft end of the bellows did you?

 

[larr630]

Re: 94 Mercruiser 4.3L v6 intermidtant shut-down

The terminals were in good shape.

Yes I put a clamp on both ends of the bellows hose. the one that was on there had a clamp on both ends. The hose seemded to short when i bought it. so i tried stretching it on a pvc pipe for two days to no avail. I think it ripped because when the outdrive is in trailer position it really stretches that tube. Did I do something wrong?

 

[Don S]

Re: 94 Mercruiser 4.3L v6 intermidtant shut-down

Yes I put a clamp on both ends of the bellows hose. the one that was on there had a clamp on both ends.

You stated you put a new tube on a month ago, and the tube doesn't get clamped onto the drive, only the bellows does.