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Start problem 90 hp Merc

D

dpboat

New member
"Just purchased a boat w. a 19

"Just purchased a boat w. a 1983 Merc 90 hp 6 cyl 3 carb. It is very hard to start,in fact could not start it last time after sitting for week in very damp weather, but seemed ok previously once it was running. I notice when cranking the engine that the starter often 'drops out' a second or 2 after turning the key, ie the starter motor gear will engage the flywheel momentarily then drop out. Would this indicate a bad starter solenoid(which seems to be built into the starter motor?)
or a weak battery? The engine will turn over normally once in a while. Also, any hints on best starting sequence? I have tried part throttle, full throttle, no throttle, and choke only. Usually results in flooded engine(lots of gas coming out the carb throats, particularly the bottom carb). This is my first large outboard, haven't worked on them before, so any advice is welcome! Thanks"
 
u just use choke only
u might

u just use choke only
u might need to rebuild the carbs
test the battery
just sounds like u need a tune up
 
"Dan,
Sounds like the plug wi

"Dan,
Sounds like the plug wires are wet and not sending the charge on to the plugs.
Check the condition of the plug wires and if they look as if they are more than a few years old replace them. An ohm test on the wires should tell if they are good or bad. The coils should be checked for cracks and over all condition. Again an ohm test will tell the condition.

As for the starter, the engine could be trying to start and the starter drive drops out of the flywheel.
It doesn't take much for the starter to drop off if the engine fires at all.
An easy test for this is to charge the battery then try and start the engine with no choke or fuel in the cylinders. If the starter is ok it will keep turning the engine over.
If you then add choke and the starter drops off it's because the engine has fired taking the pressure off the starter drive.
This can be a real pain when you have an engine that will not start as it should.

Try and fix the no run problem before you do any repairs on the starter motor / battery etc. See if you can get the engine in a place where it will dry out. Hard to believe but water can cause all kinds of problems with boat motors and spark.
Just being damp is enough to cause plug wires to fail.

If you get the engine running and still have problems with the starter then check the starting system.

Take one problem at a time and the first is to have the engine running as it should.

Good luck."
 
"Thanks for both your replies.

"Thanks for both your replies. Unfortunately the weather here has been %$#@ and it is now time to close up the cottage and store the boat until next spring, as I have no place warm and dry to work on the engine. I will repost next spring with the outcome. Have a good winter!"
 
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