1985 40hp 2stroke Loss of power

[vroberth]

After a 60 min run my motor lost power. Full throttle only produced 10mph instead of 25mph at 80% throttle. It seemed to run smooth but I just could not get it to go any faster. I run only 87 NO ethanol gas, with seafoam added. Any ideas of where to start looking?

[99yam40]

check spark on all plugs and timing

[mjf_1955]

Any alarms or warning lights going on when this happened? Did engine seem hot?
Could you have been in limp mode?

[vroberth]

No alarms or lights, its very possible that it was in limp mode. the engine was not hot or smoking, ran very smooth but just no power. i am checking the plugs and compression on monday.

[Jason2tpa]

what ive learned on here from the pros is when its an engine performance issue 90% of the time its fuel related, not compression or spark. Assuming your getting fuel to the carbs id check them first. Older small engine carbs are easy to remove. Dump the bowls with a white cloth, check for debris. Clean all the jets.

[Atchafalaya_man]

It sounds like your spark advance or carb linkage came undone in some fashion. Check all the snap-in connections, particularly for the spark advance under the flywheel.