96' Johnson will rev up in neutral but only 2500rpm in gear.. No power, need help

[cobbcfi]

Took my boat out today for a sea trial.. Not good, could only get 2500rpm at WOT in gear... In neutral I can "carefully" rev it up to 6000rpm and it sounds good, but under load I'm at a loss...

All new plugs/wires/coil packs/stator/ and compression test turned out perfect!!

What do think is going on??

TIA

 

[racerone]

It will run to 6000 RPM on 4 of 6 cylinders so it proves nothing.----Does spark jump a gap of 3/8" or more on all leads ?-----Are all wires going to the correct coils ?----How did it run for you last season ?----A Johnson or Mercury ?-----Posted in Mercury forum.

 

[cobbcfi]

It will run to 6000 RPM on 4 of 6 cylinders so it proves nothing.----Does spark jump a gap of 3/8" or more on all leads ?-----Are all wires going to the correct coils ?----How did it run for you last season ?----A Johnson or Mercury ?-----Posted in Mercury forum.

Wrong forum, my bad

 

[cobbcfi]

Took my boat out for a sea trial yesterday and all I can get is 2500rpm at WOT in gear but I can put it in neutral and get 6k (carefully) and then put it back in gear under load and only 2500rpm.. All new coils/wires/plugs/stator/fuel filter etc....

What's your thoughts.. 2 brand new batteries as well..

 

[GA_Boater]

Merged both threads to keep all the information in one place.

 

[racerone]

The motor needs a good battery to crank over fast for starting.----The ignition system itself does not use 12 volts from the battery to make spark at the sparkplugs.

 

[Scott Danforth]

Took my boat out for a sea trial yesterday and all I can get is 2500rpm at WOT in gear but I can put it in neutral and get 6k (carefully) and then put it back in gear under load and only 2500rpm.. All new coils/wires/plugs/stator/fuel filter etc....

What's your thoughts.. 2 brand new batteries as well..

thought is motor running in neutral will do so with only 2 cylinders running. that proves nothing.

you could have a fuel delivery issue, you could have a spark issue, you could have a timing issue, you could have 6 pistons with low compression.

please answer the questions in post #2 as a start. post your compression numbers.

 

[cobbcfi]

Fuel is clean and getting to the engine, all 6 butterflys are fully open at WOT

 

[cobbcfi]

The motor needs a good battery to crank over fast for starting.----The ignition system itself does not use 12 volts from the battery to make spark at the sparkplugs.

Both batteries are brand new..

 

[cobbcfi]

thought is motor running in neutral will do so with only 2 cylinders running. that proves nothing.

you could have a fuel delivery issue, you could have a spark issue, you could have a timing issue, you could have 6 pistons with low compression.

please answer the questions in post #2 as a start. post your compression numbers.

Fuel is there and compression is even along all six around 95psi.. Fluctuations go from 93 to 98 if zi still remember.. I'll give it a taste right now..

 

[cobbcfi]

Fuel is there and compression is even along all six around 95psi.. Fluctuations go from 93 to 98 if zi still remember.. I'll give it a taste right now..

Damn autcorrect

 

[cobbcfi]

Both batteries are brand new..

2ga wire running to all systems and engine... It's got the sparky power but I'll check for a 3/8 jump to see its there..

 

[cobbcfi]

Compression test is as follows;
94 92
97 96
99 92

Looking at the motor from the rear with all plugs removed and full charge on both brand new batteries.

 

[hidef]

Download a copy of the CDIElectronics troubleshooting guide. It sounds like you have an issue with the tan wire running into your powerpack. Could either be a short or a faulty sensor putting the engine into slow mode.

https://www.cdielectronics.com/wp-content/uploads/2016/12/7th-Edition-Troubleshooting-Guide_RS.pdf