compression problem

J

jolinde

Recruit
Joined
Dec 27, 2011
Messages
1
I have a 55 hp johnson sea horse, with the spark plugs in the engine it wont wind over, remove both spark plugs and the engine winds over well, even trying to use a compression tester the engine wont wind over.
I have had the starter motor checked by 2 auto electricians and both said its in good condition, I have conected the battery directly to the starter motor incase it was a wiring issue.
Anyone have any thoughts?
 
H

Haffiman

Commander
Joined
Dec 17, 2009
Messages
2,454
Re: compression problem

Provided the battery gives the needed cranking Amp's, change the starter.
 
Bob_VT

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,111
Re: compression problem

90% of the time it is corrosion INSIDE the wiring to the battery that increases resistance. Try a direct cable (jumper cable) to the battery POSITIVE terminal. Be certain to remove and clean all ground points.

Yes if that fails then it could be time for a new starter
 
5150abf

5150abf

Vice Admiral
Joined
Aug 12, 2007
Messages
5,808
Re: compression problem

Welcome to iboats.

Try jumping the solenoid, there is a big lug on the top and bottom, touch them together with a coat hanger or something and see if it will turn it over, if it does it is a bad solenoid if it still won't it is the starter or the cables going to it.

Just follow the big red cable from the starter back, it will end at the solenoid and it is a big round thing with 2 big lugs and 2 smaller wires on it, every timre you hit the starter the solenoid arcs a bit, over time it will build up and stop working.
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: compression problem

When you check the starter circuit by connecting a fully charged battery to the starter motor with jumper cables you must bypass the ground side of the circuit as well as the hot side.

When cables or connections go bad it is more often the ground cable connection to the engine block that fails. Why? Because you have a tinned copper connector bolted with a steel bolt to an alloy block. That is a corrosion factory that should be removed and cleaned as routinely as you replace the impeller.

You may have done that, but you didn't say.

Good luck. :)
 
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