Before I throw in the towel.... HELP.

[Doc_Vegas]

OK guys:

My 2001 2700 SCR with 7.4 MPI motor has lost much of its power. I changed the fuel/water seperator filter, cleaned the air intake, and looked at the distributor cap/wires. Everything seems fine, but still not much power. Temp is fine, oil pressure is fine. Just doesn't have the power. I do not think the prop is slipping, since the engine can not build the RPMs. I may try to check the wires on the spark plugs, but I doubt one came off. It does feel like a piston may not be firing, but at idle it sounds and feels normal. That said, it also seems to have a bit of a rich smell, like there is excess fuel in the exhaust (maybe).

I do see the tach. occasionally drift high for no reason, then come back down - but there is a recent post that indicates that problem may be dirty tach leads...?

The marine shops around here are uber expensive, and my wife and I are considering a major relocation, I hate to get deep into the boat - especially now. That said, I have no trailer and I am pretty much stuck to things I can do at the dock.

Any last minute ideas before I throw in the towel and call the shop?

Thanks

[seapuppy]

yeah....pull a compression check on each piston...pull all the plugs out and use a good compression gauge ....check each piston and write them down...p1=170lbs......etc....that will show if you have a blown head gasket is there any water in the oil??....what is your base timing and full advance timing???...may have a distributor problem...

how bout the carb..is it leaking at the base gasket..ie...have you checked the torque on the carb..sometimes that loosens up...

those are just a few things I'd check ..


SP

[Gazjen]

I think the carb will be missing Pup its an MPI

Take a few plugs out see if there wet if they are its spark related if not its going to be fuel related problem is with the EFI engines it could be any one of a number of sensors. once you have checked the regular things it will really need plugging in to see if it shows any codes

If it won't rev properly its not just one cylinder

[Doc_Vegas]

Thanks guys, I decided to throw in the towel. I tried a few more tweaks, but ran out of time. I am traveling in and out of town for the next four weeks, so they will have some time to work the bugs out.

I did actually look at the oil a bit. I saw a couple of small drops of what could be water. Not much, there may have been some.

I hate to think of the costs for a head gasket or higher order repairs... but, if it comes to that, is it "cheaper" to buy a new engine? Looks like Maxum went to an 8.1L is 2002....

I will post up the findings, as unfortunate as they may be.

[seapuppy]

oops...missed the mpi engine thingy.....so...If your getting water in the oil......then yeah...you have a blown head gasket...luckily it's an easy fix..just takes time....pull head...get head machined to make sure it's true...install new head gasket...new head bolts....(note...don't reuse them...they stretch....)...so...install..change oil....run...done...


a good mechanic can have it done in a few days....


SP...

[Alain]

Originally Posted by Doc_Vegas

OK guys:

My 2001 2700 SCR with 7.4 MPI motor has lost much of its power. I changed the fuel/water seperator filter, cleaned the air intake, and looked at the distributor cap/wires. Everything seems fine, but still not much power. Temp is fine, oil pressure is fine. Just doesn't have the power. I do not think the prop is slipping, since the engine can not build the RPMs. I may try to check the wires on the spark plugs, but I doubt one came off. It does feel like a piston may not be firing, but at idle it sounds and feels normal. That said, it also seems to have a bit of a rich smell, like there is excess fuel in the exhaust (maybe).

I do see the tach. occasionally drift high for no reason, then come back down - but there is a recent post that indicates that problem may be dirty tach leads...?

The marine shops around here are uber expensive, and my wife and I are considering a major relocation, I hate to get deep into the boat - especially now. That said, I have no trailer and I am pretty much stuck to things I can do at the dock.

Any last minute ideas before I throw in the towel and call the shop?


Thanks

One of my freind had the same problems with his boat, 2001 5.7 mpi. It's was the fuel regulator that was bad.

[the19hole]

My money is on the fuel injectors.

[Doc_Vegas]

Thanks again guys, keep the bets going! I am hopeful that the solution willl not be too costly..... :?