OIL/FUEL RATIO : 1958 10hp johnson seahorse

[gto]

would the ratio be the same on my 10hp as the 30hp . The guy that just worked on my motor told me 40:1

 

[Chinewalker]

Re: OIL/FUEL RATIO : 1958 10hp johnson seahorse

Hi GTO,<br /> I would go with a 32:1 ratio. That motor has bronze bearings in the center main and at the wrist pin ends of the con-rods and needs the extra oil to maintain those bearings. A lot of those old 10s have a rod knock caused by running too lean on oil and having the wrist pin bearings wear.<br />- Scott

 

[Tracy Coleman]

Re: OIL/FUEL RATIO : 1958 10hp johnson seahorse

gto<br />To correct the previous post, 7 1/2hp have bushings for bearings, but your 10 hp has needle bearings on the crank, wristpin, upper and lower bearings. Center main is a bushing.<br />Backfire

 

[Chinewalker]

Re: OIL/FUEL RATIO : 1958 10hp johnson seahorse

Hi Backfire,<br /> Hate to disagree with you, but the 1958 10hp does indeed have bronze bearings on the wrist pin - no needles.<br />- Scott

 

[gto]

Re: OIL/FUEL RATIO : 1958 10hp johnson seahorse

is 32:1 ratio good for both types. I hope not to find out which of you are correct on thr bearings.

 

[MGuckin]

Re: OIL/FUEL RATIO : 1958 10hp johnson seahorse

Most outboards of that era were calibrated to use 25:1.<br />The oil today is of much better quality and it is a widely accepted practice to use 32:1.

 

[Tracy Coleman]

Re: OIL/FUEL RATIO : 1958 10hp johnson seahorse

Hi Chinewalker<br />You are right on the wristpin bushings on the 10 hp. "Full Jeweled Power", an old Merc adage, did not occur on the OMC 10's until 1961. Ain't this fun! Backfire