1955 johnson 25 hp head gasket

[Woodstock60]

I ordered a head gasket from Laing's outboard for this motor (model # RDE-17) and the gasket was pn# 302583. Laing's listed it as pn# 3865. When I received it today all of the bolt holes lined up but the copper rings that seal the piston to the head were 1/8" bigger than the original. I looked up all part numbers again and everything seems to be right, except if I install I leave a 16th of an inch gap all around my mating surfaces. This cannot be right. Can anyone weigh in on this? Thanks

 

[F_R]

Re: 1955 johnson 25 hp head gasket

That is an interesting question. Your numbers do check out correctly. 302583 is listed as no longer available from BRP. Sierra Marine 18-3865 is supposed to be the correct aftermarket replacement, also sold here at iboats. However, that is also listed as obsolete in the 2008 Sierra catalog.

I can't answer your question as to why it is too big. Your motor is 2 7/8" bore. A 35hp is 3 1/16" bore. Do you think you got a 35hp gasket by mistake? Measure it and see what it is. Of course there is the possibility that it is a quality control problem too.

You realize that the gasket normally is big enough to allow oversize pistons to go through in a re-bore job, right? But the oversize pistons were only .020" over, total. Certainly not 1/16" (.062") on each side.

 

[Woodstock60]

Re: 1955 johnson 25 hp head gasket

Yes F_R my bore is 2 7/8, and the new gasket is 3 1/16. The orig. gasket is in good shape and is 2 7/8. the only marking on it is "victor", the new gasket says "vic-3139".

 

[Woodstock60]

Re: 1955 johnson 25 hp head gasket

Apparently the oversized gasket can be used for tis motor, or so says the guy over at Laing's. can anyone confirm this?

 

[coolguy147]

Re: 1955 johnson 25 hp head gasket

i got no clue lol

 

[F_R]

Re: 1955 johnson 25 hp head gasket

Apparently the oversized gasket can be used for tis motor, or so says the guy over at Laing's. can anyone confirm this?

"Can be"...well I suppose maybe. That doesn't make it right. It is a 35hp gasket. You might not have much choice unless you can find a NOS OEM gasket. Personally, I would try www.sea-way.com for the right one.

 

[Woodstock60]

Re: 1955 johnson 25 hp head gasket

Thank you F_R.