Slow crank 87 125

[Stokes760]

Just picked up this outboard for a song and going thew everything. The bendix was stuck up so after some lube and a few swear words got that operational. Next issue is slow crank. What I've done so far.
pulled plugs and cranks faster.
jumped the starter directly to bypass any wireing issues.
I have a feeling its toast. But its my first outboard so still learning. Thanks in advance for any help.

 

[kbh121956]

Check the compression with all plugs removed. If compression is good, is the battery fully charged? Good connections? Post your results, others will join in and help you.

 

[SkiDad]

if your battery is strong it's probably the starter - been there done that.

 

[Stokes760]

Need to bring compresion tester home from work.
I used jumper cables from my truck straight to starter so i know battry was good and bypassed the wireing

 

[jerryjerry05]

Jumper cables are not the way.
They just don't work as well as the right cables..
I have a set if you need them. You pay shipping and you can have them.
Sent you a PM.

The slow turn: bad connections, bad cables, dirty starter, low compression on 1 or more cyl.

Get the right cables, #4 is what the factory uses.
So anything heavier works better. #2 #0

The battery: a battery that shows 12v can be bad. Load test it.

 

[Stokes760]

So useing 0 gauge jumper cables from my running truck directly to starter terminals isn' the right way? I figured it would bypass the solenoid and any possible hi resistance battry leads and get the most juice to starter. Low compression would be a cause for slow crank I figured it would be the opposite.

 

[kbh121956]

It is always better to have a battery hooked up too the outboard. Some "juice" is always lost when using jumpers. JMO.

 

[Tassie 1]

Any burnt or extra hot wires coming out of the starter solenoid?
got a voltmeter?

 

[Stokes760]

Hooked up battery to battery cables same cranking speed.
solenoid looks good. Nothing to suspect.
I have a new starter comeing ill see if thats the issue.

 

[jerryjerry05]

Low comp= slow turning.
Something about the difference in pressure making it hard to turn.

I thought that it should be easier, but it's not.

Low comp kinda acts like the timing is out on a v-8 slow and then picks up then slow again.

Just take the bottom of the starter off.
Your starter could be 30 years old??
If it's never been cleaned it can be pretty bad.

 

[Stokes760]

Did comp test all were 95 to 100. Seems low but with slow crank I can' tell. I pulled starter and cleaned contacts ect wasnt any better. I'll have a starter end of week and hopefully it will help.
do people do leak down tests on 2stroke outboards? I figure as long as piston is in the top of the cylinder I could check and see how the rings are

 

[Stokes760]

And the whole low compresion slow crank still kinda confuses me. I under stand that if compresion was good you would have roughly 125psi helping in the down stroke. But my issue is starter hardly crank with plugs in. And will crank with plugs out. Even testing one hole with the compression gauge noticeably slows down cranking.

 

[Stokes760]

Put the new starter in and accuall cranks with the plugs in. Thanks everyone for leting me bounce idea off of you.

 

[jerryjerry05]

Actual compression with a good gauge: 145-150#
Different gauges get different results.
Harbor freight and a Mac Tools/Snap On will probably have a difference.

The results, even with a cheap gauge is what your looking for.
The results should be all cyl. be within 5-10 # of each other.

My 1988 85hp. when the head gasket would start to go the 5# drop was enough to make it turn over slow.

Pulling the port covers or the exhaust chest will only cause problems.
The port covers never seem to fit good unless you goop them up and let it setup.
The exhaust chest, Broken bolts and leaks will be a B to fix.