1970 65 Hp Merc

[Kaiserkid_715]

Hello All <br /> I have a 1970 65 Hp Merc 650 Thunderbolt that is realy getting on my nerves , so any help or suggestions would be greatly appreciated . <br /> This motor runs good from just above idle to full throttle . But when you try to run it at slow speeds it dies . When you start it you have to keep it running with the cold start lever , when you put the C\S lever down it will die .<br /> I did a compression test on it the results are as follows --1 Had 125 2 Had 115 3 Had 80 4 Had 100 <br /> Thease results have me very worried . What should I do from this point ? Can this be fixed or what may be the cause for such differences ?

 

[Backlash]

Re: 1970 65 Hp Merc

Well Kaiserkid, <br />Your compression test shows far too much difference between cylinders

. I'd decarbonize with Seafoam first & check the compression again. If you see improvement (all cylinders should be within 5-10 psi of each other) you're golden.........if not, you may have more serious problems, i.e., broken ring, etc. <br />Good luck.