Help. New boat owner now turned mechanic

capt bligh

Cadet
Joined
Jul 14, 2012
Messages
8
Just bought a 70 or 71 Sea King 6 hp outboard that will not crank. As I understand, the diagnosis order is :
1. Test Compression
2. Test Spark (Plugs, coil, fuse?)
3. Test Fuel (Connections, lines, carb, filter?)
I borrowed a compression tester from the local auto parts, took out both plugs, screwed the tester into the block, and pulled 4-5 times. Problem is I am getting 0 psi reading on both plugs. I have tested with one plug out as well as both plugs out. Any suggestions on if I am doing anything wrong? I suppose the tester could be faulty, but I wouldn't think so.
Just trying to diagnose the problem so maybe I can fix it myself.
Thanks for your help
 

budweisr33

Recruit
Joined
Jul 20, 2010
Messages
1
Re: Help. New boat owner now turned mechanic

make sure the valve,in the bottom of the test gauge hose, is in place(screwed in). Otherwise the tester will not hold any pressure and give a reading of zero.

Are the pistons moving while you pull?
 

capt bligh

Cadet
Joined
Jul 14, 2012
Messages
8
Re: Help. New boat owner now turned mechanic

yes I am sure I had the threaded connections in tight (by hand). Yes the pistons are moving when I pull the cord. I don't know how I would go about testing the tester. I suppose tomorrow I could test my pressure washer easily enough. I know that it's working fine.
 

brewern

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Joined
Dec 31, 1969
Messages
12
Re: Help. New boat owner now turned mechanic

yes I am sure I had the threaded connections in tight (by hand). Yes the pistons are moving when I pull the cord. I don't know how I would go about testing the tester. I suppose tomorrow I could test my pressure washer easily enough. I know that it's working fine.

Pull a plug out of another motor and do a test. If that motor produces compression, we can eliminate the gauge as faulty.
 

capt bligh

Cadet
Joined
Jul 14, 2012
Messages
8
Re: Help. New boat owner now turned mechanic

Pull a plug out of another motor and do a test. If that motor produces compression, we can eliminate the gauge as faulty.

I will try that tomorrow and see what happens. Thanks
 

capt bligh

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Joined
Jul 14, 2012
Messages
8
Re: Help. New boat owner now turned mechanic

OK...today I pulled the plug out of a 5hp honda motor that is working fine, screwed the tester in, and pulled the recoil starter 6 or 7 times. I did this twice and got 0 psi reading on this motor as well. So I'm either stupid, or the tester doesn't work. I think I will take it back and go to another parts house and borrow theirs, or I will spend $40 bucks and buy one. I'm sure I will never need it again.
 

emoney

Commander
Joined
Jul 19, 2010
Messages
2,551
Re: Help. New boat owner now turned mechanic

If you have a Harbor Freight you can buy one for $10.00. Handy to have around.
 

capt bligh

Cadet
Joined
Jul 14, 2012
Messages
8
Re: Help. New boat owner now turned mechanic

OK...went to another auto parts house and borrowed their testor and just tested both cylinders. One tested at 58 psi and the other at 60. tested both twice, same results. So the first tester was bad after all. Not having a service manual, I don't know if this is adequate compression.
 
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