Marnier cooling problem

[Jhdavis18]

I have a 5 hp Marnier, Japaneese made, serial number 152381 which I believe is 91-95 vintage. The engine runs fine and there is a good water flow from the pee hole at idle. As the RPMs are increased the water flow decreases and ultimately stops. I see from other articles that this may be an exhaust leak preventing the water flow. Any other ideas? I hate to have to pull the head cover( break the bolts) if I don't have to. I have installed a new impeller so that is not the problem.

 

[Laddies]

Re: Marnier cooling problem

Did you clean out the impeller pieces from the old impeller, some times the drop down in the intake and as RPMs come up hey shutoff the water flow or in some cases they are up the water tube and the pressure does the same thing, ck the intake and backflush the engine down the tube

 

[Jhdavis18]

Re: Marnier cooling problem

Thanks Captain, I have done all this. I have checked for old pieces. I have blown air through the system. I now have the power head off and removed the cylinder cover revealing a significant deposit of salts etc. I have cleaned this out and currently have the power head upside down and have filled the water jacket with vineger hoping it will desolve any scale or salt elsewhere in the cooling system. any other suggestions?