91 Merc 175 XRi suddenly quits. can restart.

[mayatan]

I have a1991 Merc 175 XRi that one day died when I was taking 4 friends for a ride. It was just like someone pulled the tether out. from 5200 rpm to 0. no sputter or coughing. I wouldn't restart right away but after 2 minutes it fired up and ran just fine. I got up on plane and cruised around for 15 minutes at 3200 rpm fine. Later alone I took it out, ran 3500 ish rpm fine for 8 minutes. I opened it up and it died again. same way no warning or hinting, just died. fuel bulb was hard. same restart. nothing right away but after 2 or so minutes it fired up like nothing was wrong. I limped home at 3k rpm just fine. I pinned it right near my dock and it died again, after about 20 secs. Next day same thing but dies sooner. just up up on plane and dies, no warning nothing. this time it would not start and I towed it home all 2 blocks!

I checked the tether it is fine, the fuel bulb is always full. I spun off the fuel filter and the gas was under a lot of pressure. It sprayed out a few ounces of gas at a pretty high psi while I was unscrewing it.

Put my other filter in, no difference.

So , anybody have any ideas?

 

[ufm82]

Re: 91 Merc 175 XRi suddenly quits. can restart.

If it dies like you just yanked the cut-off lanyard then it's not fuel, it's electrical. With an instant shut-off like that I'd be at the kill switch, ignition switch, harness, battery cables, etc for a short/unintended connection. Look at the harness on the engine for any sign of wear/rubbing/heat exposure. Look closely at all joints, connections, anywhere the cable make a bend around metal, etc.

 

[Sprky]

Re: 91 Merc 175 XRi suddenly quits. can restart.

Anytime they die under a load you have to worry about a seizure, especially since it would not crank back up without sitting. Do a compression test to rule out that issue. Then start looking elseware.

 

[mayatan]

Re: 91 Merc 175 XRi suddenly quits. can restart.

Thanks for the replies. When it had to sit, it was only for about 90 seconds to 2 minutes then it fired up like everything is fine. The first few times it would get up and go and have no trouble running at 3 to 4 k rpm. when I pinned the gas pedal while going say 38 mph it would die within 2-6 seconds. I am not sure how that would be an electrical issue. If I did not pin it while going 35 mph, it would stay cruising at that speed for ever. I am not saying it can't be electrical, just not sure why it would run at lower speeds.

Are there any electrical components to the fuel pump?. It is in the shop now and hopefully they look at it next week but I am thinking fuel pump. I hope!!!!