PO 15 issues

[stanley]

Last season this motor ran great with the exception of a small water leak in one head gasket.The leak was to to the outside,not into the cylinder.I put a little sealant on the gasket and all was well.Ran the motor several times without any problems.Just tried to run it yesterday and had a heck of a time getting it started,it ran poorly and the head that was leaking last year was overheating.I can think of reasons for each problem seperately,but wonder if there is a common problem or just a series of coincidences.(It has 90psi on both sides and good spark.)

[Anonymous]

Possible plugged cooling line or and air leak that causes a steam pocket blocking the water flow.

[jerry-ahrens]

Try replacing the copper water lines on the front of each cylinder with clear flexible tubing. When you run the motor on a boat, it will be easy to see if your’e getting water flow to the cylinder. This is a pressure vacume cooling system, so it’s essential that all lines, fittings etc. are air tight.
I’m sure you realize that the PO 15 needs to be throttled up immediately after starting, to allow the system to fill with water. This ”primes” the cooling system, so that after the engine is slowed down to a trolling speed, the vacume part of the system will keep the flow of cooling water constant. Any vacume leaks through out the system will cause a loss of prime, and result in overheating.
Here is a pic of my V45, with the clear hoses. I wrapped the threaded fittings with teflon tape, then used a hose clamp to secure the tubing. This protects the tubing from being ”chewed up” by the fittings threads.

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[dan-in-tn]

Jerry; You know you just wanted to show us your GREAT looking engine! She is a dandy. The clear hoses are a great idea and should diagnosis his problem. See you in Tomahawk, I hope you are feeling better?

Dan in TN

[jerry-ahrens]

Thanks Dan, doing a little better. We are hitting the road on Monday, so I can break the trip in half. I should be there Tuesday afternoon sometime. See you there!

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