2004 Mercury Optimax Pro XS 225 died WOT

[sbecker01]

I have a 2004 Mercury Optimax Pro XS 225 with abut 700 hours on it. Serial #1B106138. I regularly maintain it. Last Saturday I left the ramp and had run about 4-5 miles up river and my motor shut down. There was no noise, alarm or smoke. There was no oil anywhere. I tried to start it and it turns over extremely slow and will not start. What happened? Any advise would be appreciated before I take it to the repair shop. Thank you.

[lpugh]

Test battery first and verify good connections
remove the compressor belt and see it cranks ok
verify alternator and compressor will rotate, the comprssor will get harder to turn as the piston rises to develope pressure
perform a compression test
report back

[sbecker01]

Test battery first and verify good connections
remove the compressor belt and see it cranks ok
verify alternator and compressor will rotate, the comprssor will get harder to turn as the piston rises to develope pressure
perform a compression test
report back

Would the battery have caused it to die while I was running wide open? I can check the battery, but my repair man will have to check the rest because I don't trust myself to do it.

[EuropeanAM]

Possibly- but check the basics as well (Leon gave you some good starting pointers).

[sbecker01]

Possibly- but check the basics as well (Leon gave you some good starting pointers).

Thank you. I will check everything that I am comfortable doing. Other than that my dealer will have to do the rest. I'd just like to give him some kind of idea/direction.

[sbecker01]

Test battery first and verify good connections
remove the compressor belt and see it cranks ok
verify alternator and compressor will rotate, the comprssor will get harder to turn as the piston rises to develope pressure
perform a compression test
report back

I took the belt off and I can't get my compressor to turn clockwise. It will turn a little ways counter clockwise, but not too many times around. When I try to start the engine the belt drags on the compressor pulley. Should the compressor pulley turn when trying to start?

[lpugh]

I took the belt off and I can't get my compressor to turn clockwise. It will turn a little ways counter clockwise, but not too many times around. When I try to start the engine the belt drags on the compressor pulley. Should the compressor pulley turn when trying to start?

Compressor must rotate to build air pressure. Should be able to rotate by hand, it will get harder turn thru the compression cycle, When you say drags, do mean it stops turning or the belt is slipping.

With the belt off does the motor turn over at a normal cranking speed.

Sounds like you may have a compressor failure which would cause your symptoms, you can pull the head off of the compressor for inspection easily. With the head off it should rotate easily and smoothly
If the compressor has failed the complete fuel rails will need to be sent to Don (European Marine for service)
If the motor cranks properly with the belt off. Perform a compression test with throttle wide open and kill switch cord pulled, with a battery charger on the cranking battery operating. Readings may be a little low but should within 10% variation max.
Be sure this is done before any other repairs are performed. Need to be confident in what total repair cost will before beginning work

I would highly recommend this job be performed by a certified Mercury Tech and I would insist the fuel rails be sent to Don for validation

[SilverFox579]

If you cannot rotate the compressor pulley by hand with the belt off, the compressor is done.

[sbecker01]

Compressor must rotate to build air pressure. Should be able to rotate by hand, it will get harder turn thru the compression cycle, When you say drags, do mean it stops turning or the belt is slipping.

With the belt off does the motor turn over at a normal cranking speed.

Sounds like you may have a compressor failure which would cause your symptoms, you can pull the head off of the compressor for inspection easily. With the head off it should rotate easily and smoothly
If the compressor has failed the complete fuel rails will need to be sent to Don (European Marine for service)
If the motor cranks properly with the belt off. Perform a compression test with throttle wide open and kill switch cord pulled, with a battery charger on the cranking battery operating. Readings may be a little low but should within 10% variation max.
Be sure this is done before any other repairs are performed. Need to be confident in what total repair cost will before beginning work

I would highly recommend this job be performed by a certified Mercury Tech and I would insist the fuel rails be sent to Don for validation

Thank you very much for the advice. I will try to crank it this evening with the belt off. When I hit start with the belt on it wants to start for a split second then slows way down. With the belt on the spindle is turning the fly wheel and the alternator, but the compressor pulley is not turning. The belt is just sliding across the compressor pulley.

[sbecker01]

If you cannot rotate the compressor pulley by hand with the belt off, the compressor is done.

Yes, the compressor pulley will not turn by hand with the belt off.

[JOE54]

^^^^^ YUP

[sbecker01]

I just wanted to thank everyone that helped with ideas. It was the compressor. My dealer is currently cleaning the fuel lines and rails as well as replacing the compressor. Thank y'all!