90hp two stroke bogging down

Hi

I purchased a boat a few months ago which I know has only been used a few times in the last 3 years. It has a 1986 90hp Two stroke which starts and runs fine out of the water, revs freely while in gear, but in the water, it will not rev over 1800 revs it so, just bogs down. I replaced the filters, drained the fuel, installed a new tank and fresh fuel, but I suspect the carburettors may be clogged and will need rebuilding, due to old fuel that has been left in them.

I checked the compression and this is fine. Strong water flow from the water pump in the tell tale and no high temp alarm, it has these syptoms from first running on the water so I don't think it is a temp problem.

Appreciate your opinion if you think the carbs could be to blame before I book it in to the shop to have them rebuilt.

Thanks,
Ken

[boats.net]

Yes the carbs would need to be cleaned after sitting that long.

Check oil system

If you have a precision-mix oil system, the RPMs will be limited to 2,000 if the tank in the power head drops below the minimum level.

The problem was two fold, first off, the carbs needed cleaning and the motor was only running on two cylinders, which wasn't obvious to me until you loaded the motor up. The CDI unit was faulty and needed replacing (fortunately sourced a second hand unit which saved some $)

Cheers and thanks for the advice