Name:   cobra - Subject:   Cat, maybe you can shed some light Date:   9/1/2014 9:00:12 AM (updated 9/1/2014 9:18:08 AM)

  I have talked to you several times on the phone. You suggested I try the four blade prop on my 20 foot Sylvan Pontoon boat and so far it does great. I installed a new OEM Mercury 50 hp 2 cycle power head on this boat in the spring. I rebuilt all three carburetors and of course replaced all fuel lines. I run non-ethanol gas with sea foam added often.

       The one small problem that worries me is when its cold and first starting off I can get 5000 to 5200 rpm's at full throttle. Yesterday it would scream and I thought finally this engine has broke in. I went about two miles and let it sit for about an 30 minutes. When I started back across the big water I could never get it over 4600 rpm's . It just did not have the same sound as when I first took off. I just want to make sure this engine does not blow like the original one did. I am using the oil injection as all the parts were new on the new power head. It is using oil from the tank so I  do I know its working. I also am still mixing about an once per gallon to be on the safe side until this engine has about 50 hours on it.

     I tested the compression about two weeks ago and all cylinders are 120 psi. I had tested the compression with the engine cold a few days before that and all I could get was 95 psi but they were all even. It did sort of worry me but I was told this was fine. The next time I tested the compression I made sure the engine was warm and the throttle was at wide open position and thats when it showed 120 psi. I am a mechanic and been working in things for over 50 years but not much experience with marine engines. I do understand 2 cycle engines as I have worked on many in the past except boat engines.

    It may not be anything to worry about but it was showing the same signs as it is now just before the other engine went south. I am planning on installing a heat gauge to monitor the temps, just to be on the safe side. No alarms on this boat works and from what I read the oil alarm is not much good anyway as it only monitors how much is in the tank. I never let that get low. Thats why I am installed the temp gauge to see what my engine is running at. Like I said I may be just paranoid about all this but after spending what I did I want to make sure this new engine lasts me a long time. Thanks for any help and always enjoy reading your replies here. You do know marine engines. I just wish you were close to lake martin.

   One thing I have not checked and I know I should is the fuel filter. I thought I had told the person that helped me install this engine to change it but to tell you the truth I never checked. I need to replace it first and then let you know. Will any aftermarket work ? Maybe 5/16 inline that I could take with me. This is a 50HP Mercury 2000 model.  I will post back the results. I also will install a water seperator filter on it and maybe some clear line to see if I am getting air. What you think on this suggestion ?

Thanks