1992 90 hp Nissan Outboard - rpms drop to 2800 and wil not come back??

[warrior-p]

1992 90 hp Nissan Outboard - The boat will take off and run 5000 rpms for a short piece and then drop to 2800 and will not come back. It acts like the carbs are dirty but I had them cleaned this week where he did not find anything, but proceeded to give them a thorough cleaning. I know there is a temperature, low oil, & water pressure sensor that can reduce the rpms. But last night it did the same thing right off the bat so I stopped and fished for three hours and then went back to the launch. I ran the outboard and it would cut in & out at full throttle but run fine on 3/4's throttle. Is their a specific ohm reading I can check the coils and sensors? It acts like it is not getting gas but everything is clean. Any suggestions???? Thanks

You can call me at 318-347-2008 if it easier than typing.

 

[TOHATSU GURU]

Re: 1992 90 hp Nissan Outboard - rpms drop to 2800 and wil not come back??

The test procedures for the ignition system can be found in the service manual for that model engine.

 

[warrior-p]

Re: 1992 90 hp Nissan Outboard - rpms drop to 2800 and wil not come back??

Alright - Nissan guys - I need some help:
I have cleaned the carbs, verified all sensors are working properly (water, oil & temperature), ohmed out the coils, cleaned the carbs, drained/cleaned the gas tanks and the motor still NO WORKY! I replaced the plugs yesterday and ran it again where it appears that the bottom cylinder is not firing. Coil is good. What should I try next? :'(

 

[warrior-p]

Re: 1992 90 hp Nissan Outboard - rpms drop to 2800 and wil not come back??

Alright - Nissan guys - I need some help:
I have cleaned the carbs, verified all sensors are working properly (water, oil & temperature), ohmed out the coils, cleaned the carbs, drained/cleaned the gas tanks and the motor still NO WORKY! I replaced the plugs yesterday and ran it again where it appears that the bottom cylinder is not firing. Coil is good. Compression on all three cylinders is good. What should I try next? I am getting desparate.

 

[TOHATSU GURU]

Re: 1992 90 hp Nissan Outboard - rpms drop to 2800 and wil not come back??

Did you test every ignition part in the system against the factory specs as found in the service manual or did you just the ignition coils for resistance?