Force 1989 150HP Slow cranking problem. Please help

[cliff_fulton]

I have a 1989 Force 150HP A model. The engine is in great shape and was hardly used prior to my purchase.
Ran the engine most of last year, and it ran very strong. At the end of the season, while idling the engine stopped. When I tried to crank it, the cranking speed was very, very slow and labored.

What I have done so far.

New Starter, and applied power directly to the starter, still very very slow. Also, jumped the hots on the solenoid, and still cranked very slow under compression.
Took out bottom plugs, had some milky white gas, which I cranked out until clean.
Replaced the header gasket and resealed.
Still very slow cranking speed under compression. When I take out the spark plugs, it cranks strong.

I am at a loss with what to try next? The engine is like new.

Any help would be great, thanks
Cliff

 

[pnwboat]

Re: Force 1989 150HP Slow cranking problem. Please help

Make sure the battery is good. If you're using jumper cables they can fool you. Standard jumper cables either aren't thick enough to carry enough current, or the alligator clips on the end are not heavy duty enough to make a good solid connection. Make sure all the battery cable connections are free of corrosion. Disconnect the battery cable connections and look at the under side of the connectors. Take a wire brush and clean them off. I have to do this at the beginning of every season. Top exposed side of the connector looks fine. Take the connector off and look at the other side, almost solid corrosion.

 

[Frank Acampora]

Re: Force 1989 150HP Slow cranking problem. Please help

Don't even check--buy a new high capacity battery. The starter on the 150 is the same starter used on the 3 and 4 cylinder engines. THUS: to crank that big 5 cylinder engine it needs to work much harder. If your battery is even slightly sub-par, cranking will be a problem.

And, as said above, jumper cables will fool you

 

[jerryjerry05]

Re: Force 1989 150HP Slow cranking problem. Please help

The first thing to do is check/clean the starter.
Then load test the battery.
Then do a compression test.
Low comp in 1 cylinder will cause hard starting.
Water in the cylinder can be the head gasket,or the gasket in the exhust housing.
What condition was the gasket?
Sealing the head gasket,not needed.
You add sillycone or a sealer,it gets in the cylinder and it can/will burn and make a hot spot causing gasket failure.
Jumper cables are ok for charging not really good for jumping.Most are only 12ga.Not very big.
Compression test is the biggest question.
The results should be all within 5-10 # of each other.

 

[cliff_fulton]

Re: Force 1989 150HP Slow cranking problem. Please help

I looked at many post before posting. I think that I have eliminated the power, as I have used a very high powered 12 volt power pack, as well as a new battery. I have gone directly to the starter with full 12 volts.

With the spark plugs out it cranks fast. With 1 it cranks fast, with 2 or more it cranks very slow.

I took the head off and blew out any water, and have replaced the head and gasket. Also, I looked at the cylinders and they look very good condition to me (non mechanic eyes)

What else could it be, if the starter works under no load, but with the plugs in it is very very slow cranking?

 

[pnwboat]

Re: Force 1989 150HP Slow cranking problem. Please help

I would begin to suspect the starter itself if you've eliminated everything else. Might do as Jerry suggested and take the end cap off the starter and take a look at the brushes and check the overall condition of the inside of the starter itself. If it looks like any of the windings are burnt, then that may be an indication that the starter has been overheated at some point and may be suspect.

 

[jerryjerry05]

Re: Force 1989 150HP Slow cranking problem. Please help


1 of 2 problems? You need to do a comp test and rebuild /clean the starter?
These pics are from a working,yet weak starter.
Take yours apart and see??
The comp test,remove all the plugs?Jump the solenoid at the motor.
Profile? Location? You might be close to someone who can help.

 

[pnwboat]

Re: Force 1989 150HP Slow cranking problem. Please help

I just noticed on your first post that you said you have a new starter. Might check the voltage drop across the starter solenoid when cranking. Anything more than a volt or two difference, might indicate a bad starter solenoid (burnt up contacts inside the solenoid). Also OHM out the battery cables. Each section of battery cable should read .5 ohms or less. 5- 10 ohms or above would indicate a bad cable. If that all checks out then don't rule out that your new starter might be bad.