'59 35hp exhaust inner cover plate pn's? big twin

reading the seloc manual for my '59 johnson 35hp, rds21b, and it makes mention of the innner exhaust cover, and how in that era, it's frequently made of aluminum...and that if it's used in salt water, like mine is, it may corrode through. i have no evidence that this has happened to mine in the way it runs, but it has me scared that i ought to do some preventative maintenance, and replace it with the stainless version that they say is the proper replacement part.

from earlier posts, some of you appear to have a way to tell what various part numbers should be.

first, i want to ask if you know what that part number is, and or a place that sells it.

second, as to not be a burden on this list, i don't mind looking up my own part numbers, if someone can tell me how to do it. should i invest in the parts manual? are it's part numbers still valid? many have been superseded, so it make me wonder.

-peter

Re: '59 35hp exhaust inner cover plate pn's? big twin

This may not be relevant, but the inner cover on my '69 40HP was stainless from the factory. What is relevant is that when trying to take off the exhaust cover on an old saltwater motor, you may bust off several of the bolts doing so. I had no choice, since my outer cover sprung a major leak. I had to drill out probably 6 of the bolts, even though I applied major league heat to them. A hint if you have to drill the busted ones out: put the cover back on with a couple of the remaining bolts, and use the exhaust cover as a guide for the drill bits. Another hint: use a cobalt drill bit. Another hint: use a left-handed twist cobalt drill bit. Last advice: never use an EZ out.

You may be able to determine what material the inside cover is made from by looking at an exposed edge of the exhaust cover on the engine. You may be able to see the inner liner edge, and try to scrape it with a knife. You'll be able to possibly scrape some metal from an aluminum liner, but wouldn't stand a chance of shaving it if it were stainless. I'd place my bet on it being stainless........

Re: '59 35hp exhaust inner cover plate pn's? big twin

oh, how i hope you're right...but the manual says that they were aluminum up until the early '60's, but that the _replacements_ are stainless.

-peter

Re: '59 35hp exhaust inner cover plate pn's? big twin

I don't know enough about the '59 model to contradict the manual, so I'd definitely try to find an exposed edge of the inner/outer cover "sandwich" to see if you can determine if the inner one is aluminum or stainless. If somebody doesn't pipe in that has specific knowledge of your particular engine, you may call Sea-way marine to see if they can help you out:
http://www.sea-way.com/contact.htm
Good luck! Replacing the outer cover on my 40 was not one of the funnest things I've done....

Re: '59 35hp exhaust inner cover plate pn's? big twin

thanks for the tips! i'll definitely get about determining the composition of the inner cover asap. if it's aluminum, i may just pony up to the local machine shop and have them deal with the frozen bolts. my experience with frozen bolts has told me that there is a bit of "artisanship" in deciding the proper course of action to extricate them, or how do the least amount of damage. and i don't want to use an irreplaceable engine block to learn on. maybe i'll have them pull the top seal if i determine that it's laking and not just an overgreased armature.

-peter

Re: '59 35hp exhaust inner cover plate pn's? big twin

This is definitely a case of the "If it ain't broke don't fix it" repairs.
Drilling out broken bolts is tricky in the best of circumstances.It often ends up in disaster.
Unless your engine is super loud and the outer exhaust cover has signs of the paint burning off,don't touch it!!

Re: '59 35hp exhaust inner cover plate pn's? big twin

say, suppose the worst case, in which i have the aluminum inner cover, [though i really hope it's stainless]. i use this engine primarily in the ocean, but i keep the boat trailered and dry, and i always flush with my garden hose when i'm done. is there good reason to hope i can keep the aluminum inner cover healthy with religious fresh water flushing after use?

-peter

Re: '59 35hp exhaust inner cover plate pn's? big twin

The better you flush AND wash the salt off the engine after salt water use the longer it will last.
It has held up for 50 years so far,it will probably hold up a few years longer