Mariner 150 Intermittent Problem

Hello. Iíve got a Mariner 150 efi, 95, and have had an intermittent problem. Sometimes on take off it bogs down and has barely enough power to plain out. Suddenly it will kick in and go as if a switch is being cut on and off again. A little history on what I have found and replaced.....

 Found a burned out regulator, replaced both "40amp".
Replaced both switch boxes.
Checked fuel flow from tank to fuel rail, and pressure, and voltage to pump according to manual. All checked ok to specs.
Preformed resistance test on trigger assy. Found something a little funny there. All test spec out ok but I can pull on the harness at the flywheel just slightly, and watch the readings on meter fluctuate sometimes fall below specs. Not sure if that is ok.
Now this thing runs fine in the tub, but not on the lake!
Iíve also tried using a spark tester an tried a timing light while its idling and pulled on the trigger harness and cyls keeps a spark.
Iíve checked every possible connection from battery to engine for bad connections and corrosion nothing there.
I think Iíve narrowed it down to ether the stator, trigger, or spark advance module. But Iím not really confident in that its one off those things. Any advice would be GREATLY APP!

Thanks in advance, Keith

 

Keith,

Sounds like the prop is hooking up too hard and causing the motor to bog. Add some vent holes and it will probably cure the problem. If you can, run it on a test wheel (prop) and see if you can verify if the RPM and acceleration is proper. I would try these things or if you have no access to these, just try a different and smaller prop and see if the problem goes away on take-off.

Randy

 

 

Please submit whatever questions you have to IHRTechTalk@yahoo.com.  All questions and answers selected will be displayed on this page as they come in.  Note: though all boaters are welcome, priority may be given to I.H.R. members.  Randy can not be held responsible for any advice given.  Though his information and expertise is second to none, he has no control over what you do with your boat.  It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.

Thanks,
Mark C.

 

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