Mercury problems

**HarleyMan08** · 04-22-2008, 10:13 AM

Originally Posted by DTG

My bulb needs pumping up by the time i get home, is that normal?

I agree with stinkies daddy, my pontoon has been doing something similar to what you are describing & it's getting air somewhere, as long as you are pumping it, it runs fine, but you stop & it dies, could be the carb jet too, I've experienced that, if it turns out to be the carb, I put a can of Seafoam in my gas & it will help it clear out.

But I would say you are getting air in the lines somewhere, just my opinion :D

**DTG** · 04-22-2008, 12:26 PM

We tried pumping bulb and it was tight at wot.

**DTG** · 05-11-2008, 01:47 PM

Found my problem. Piston 1 fair, 2 trashed ,3 trashed= new short block-$2700 Mechanic said it could have been from trimming motor to high and sucking air. Motor is set to high on boat so dropping it.

**scoremaster** · 05-11-2008, 02:23 PM

what would trimming your motor to high have to do with trashed cylinders unless it was way overrevved ?
just asking info is always a good thing !

**wannabe fisherman** · 05-11-2008, 02:46 PM

Originally Posted by scoremaster

what would trimming your motor to high have to do with trashed cylinders unless it was way overrevved ?
just asking info is always a good thing !

trimmed high sucking air, sounds like over heating, not getting enough water to keep cool = burned out engine.

**Barnacle Bill** · 05-11-2008, 02:49 PM

DTG, another thing that could have caused your problem is the fuel pump. If your's is the square shaped one. If your motor falls into this range make darn sure it gets rebuilt with the new style check valves or else you will have the same problem with a new block.

The new plastic check valve started in production at the serial numbers listed below.
MERCURY/MARINER USA Belgium
200 - 250 HP, 3.0 Litre Carb/EFI/Optimax S/N 0G925400
135 - 200 HP, 2.0/2.5 Litre Carb/EFI/Optimax S/N 0G912213
75 - 125 HP, 65 Jet S/N 0G923899 S/N 0P054758
40 - 60 HP S/N 0G919929 S/N 0P054357
30 - 40 HP S/N 0G919618 S/N 0P054357

This info comes from a Merc TSB

**DTG** · 05-11-2008, 08:27 PM

Yea but you think my overheat alarms would have went off. They work cause we tried them. The motor run fine the day before we took it in. Never had a problem much out of it. Run and pee'd like a champ.

IBfishn- I'll check but i bet comming from Mercury they'll send the good stuff. He's gonna go through it and clean it all and check everything so maybe we'll be good.

**grits and gravy** · 05-15-2008, 12:44 PM

Their are several possible causes for the scorched pistons. If your engine is not overreving I would suspect that you are not pulling the water intakes out of the water. Mercury waterpump impellers are pretty bad about not lasting long. My XR6 gets the impeller changed every year. The wings on the impeller are pretty short and can wear down very quickly, the newer models have longer wings and tend to last a bit longer. Next time that you take your boat out, get it on plane and trim it out. Watch your water pressure gauge and if it is sucking air it will drop down to nearly nothing. If the pressure stays high, then you may have had other problems; ie: low oil levels, reeds may have chipped, bad water pump, plugged water intakes, or just about any number of things.

**Crappie 1** · 05-09-2012, 08:37 PM

Just took my motor back to the dealer. Been having alarm issues since I bought it last year. The other night I was coming in wide open, the alarm went off and it slowed right down. This is a 30hp 4 stroke. It was smoking, I thought it was on fire. Dealer suspects it's blown. Still under warranty. Should I accept rebuilt? New power head? Or get a lawyer?

**Tracker123** · 05-10-2012, 12:19 PM

nope. start with checking all your fuel lines and then move on to the fuel pump. i think your sucking air, but not enough til their is a greater demand for fuel

x2

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