350 MPI Spark

[rned]

I have been trying to solve a lack of power and upper RPM. I have been reading many posts and replaced may parts. To date I have replaced the distributor cap, rotor, wires and plugs. I checked the fuel pressure while operating on the water, 42 to 45 #. I had an intermittent pop, mostly at lower or idle. ran the boat on a separate rank with new gas and the pop went away. I siphoned all of the gas from the tank. After all of this I still have the poor power and lack of top speed and RPMs. I purchased a GTC505 engine analyzer and and the voltages for each cylinder are between 6.2 to 6.5 Kv.

Is that voltage acceptable? What would you recommend next. I have checked the distributor cap on the lake and can not find any evidence of moisture.

The boat is a 2006 Monterey with 60 hours, of which 20 I have put on the boat since I purchased it this spring. The engine serial number is OW613417.

If I cant get to the bottom of it myself it's off to the dealer on Tuesday for a scan and analysis.

Thanks
Ron

 

[alldodge]

Sounds like your going to need a scanner to read codes. Your motor has the HVS distributor and right now I don't see an issue with spark. Bring the motor around to TDC on number 1 cylinder and check the location of the rotor to distributor location in pic below



If this is correct, do a compression test

 

[rned]

Thanks AllDodge. The boat only has 60 hours. When I bought it it had 38 hours. When I drove it for the second time I noticed it was not going above 4,000 rpms. When I turned the boat around and went into the wind it went to 5,000 rpms and a 50 mph top speed. From that point on the performance has been intermittent. For some time it worked great and then went back to the problem. Would that be a characteristic of a compression problem?

I was thinking of buying a code reader from

At first I thought it was fuel. After I ran it on a small tank with new gas it didn't help. I was thinking it was either electrical or fuel injection. I will check the distributor tomorrow. I guess I am hoping it isn't compression related.

I was thinking of purchasing a Rinda code reader. I opted for the GTC thinking it would help me isolate a particular cylinder and then check compression and the fuel injection.

Thanks again
Ron

 

[QBhoy]

Hi Ron

Welcome to the mpi fault club !
Check out some of my posts. Great engines when they are running....pain in the bum when they aren't.
I am still occasionally plagued with random 90% power gaurdian modes.
A fairly useful tool is the Mercury vessel view mobile. It tells you the faults on most occasions and I'm certain it will be cheaper than the rinder tool.
So far I've had to change
Diz cap, rotor and leads (inc spark plugs)
Iac valve (made a difference for a while)
Throttle position sensor
SW pressure switch.

After all these and a ecm reset by the dealer....touch wood, all seems well...but none of the above made an instant difference and I'm not certain it won't throw up a gaurdian fault at any given time it pleases.

 

[rned]

I wasn't aware of the Vessel View. Since your comment I was reading about it. Does it provide any and all faults? Would you know what it monitors and displays for a 2006 MPI engine?

Thanks
Ron

 

[rned]

I took the boat to a dealer. They found the problem. It was paint in the cool fuel canister.which got into the injectors.

 

[QBhoy]

I wasn't aware of the Vessel View. Since your comment I was reading about it. Does it provide any and all faults? Would you know what it monitors and displays for a 2006 MPI engine?

Thanks
Ron

Hi Ron...yeah it shows all faults. Tells you some in writing and others are just codes to look up. Very handy.
Well worth it just for the true reading the engine kicks out like rpms and voltage. They are a world away from what the anolouge faria gauges were telling me ! Superb for setting up the prop alone.
The most useful function I found was the fuel computer function telling you range, exact moment consumption, time left etc. Gives you real peice of kind and is 100% accurate. It's calculated using each pulse of the injectors. Lots of other gadgets on it too that I don't use, but will be useful to someone.

 

[QBhoy]

It will certainly work for your engine. All mpi from 2003 onwards for sure. Mine is a 2003 and works a treat.