58 Evinrude Bigtwin 35

[Trackbolt]

I was tinkering with our old '58 Evinrude Bigtwin 25 this afternoon and my son reminded me of something that he noticed the last time we used the motor in 1997. He pointed out an area below the powerhead behind the steering kingpin where he had noticed an olily streak running down the leg. He sparked my memory and I did remember it. It ran from directly under the cowl to a few inches above the exaust/water outlet on the back side of the leg. I figure it was unburned oil but I never looked too hard where it came from. I inspected the area beneath the powerhead today and the area is still kind of greasy. I rember now wiping the oil off with a rag. At the end of the season I washed and waxed the motor and hung it on the stand where it remained for the past ten years.
Now that I have new coils, points and water pump ready to install should I be looking into removing the powerhead and replacing the lower crank seals? The motor has been well cared for and properly stored but... It is a salt water motor. I am very wary of the difficulty removing the fasteners which attach the leg to the power head. Any Ideas on the source of the oil? Or am I being too concerned?
On the bright side compression is 120 psi in both cylinders and the lower unit oil was almost as clean as it was when I installed fresh oil in the beginning of the 1997 season. No water.
Any help is greatly appreciated;.

Tony

 

[1730V]

Re: 58 Evinrude Bigtwin 35

Most likely it is the powerhead to leg gasket. Are you sure all the bolts are snug?

 

[Trackbolt]

Re: 58 Evinrude Bigtwin 35

I have the IPL for this motor and figured that it might be the gasket or lower crankshft seal. The bolts are not loose or at least I cannot back them in or out with normal effort. Near as I can tell there are a few hex head bolts and a few fillister screws all stainless steel. Impact driver to loosen them? I have manual and air impact drivers. We have had the motor since new and I know the leg has never been seperated from the power head. Salt water, stainless steel and aluminum bosses are a bad combination. I can feel the bolts and screws twisting off just thinking about it. I work on small engines but don't often have to deal with stainless steel breaking off in aluminum. Mild steel in aluminum is bad enough to drill out. I checked with the local Evinrude dealer and both the gasket and seal is still available.

Thanks

Tony

 

[1730V]

Re: 58 Evinrude Bigtwin 35

It's worth a shot. If the engine has been flushed regularly, you might be surprised.

I would be careful with the impact. When removing the bolts/screws tighten them GENTLY first before loosening them. When backing them out go tight/loose to let debris come out of the holes.

 

[Trackbolt]

Re: 58 Evinrude Bigtwin 35

Initially it had not been flushed. I don't think my dad ever flushed it at all. It always got a thorough wash down on the outside after each use but I don't remember it ever running in the trash can. The owners manual says that flushing was not necessary and that was good enough for him. He last used the motor in the late 70's and I began using it in the early 80's. I usually ran the motor in a trash can after being out on the water. Flushing or not those bolts are going to be a pain.

Thanks

Tony

 

[F_R]

Re: 58 Evinrude Bigtwin 35

IF the seal is indeed leaking, you wouldn't see it. It would just run down the inside of the housing and out the exhaust. Anything that is supposed to be inside the housing is sealed from the outside by the powerhead gasket. Now before you get excited about oil running out the exhaust, that is perfectly normal. Those motors deliberately dump the crankcase drainage out through there. In fact, it is dumped in the same area as the lower seal that you are worried about.

Bottom line: I don't know if your lower seal is bad or not. Neither do you. You can't see it, nor leakage from it. As for the gasket, leakage is possible, but other than the mess it won't hurt a thing.

 

[Trackbolt]

Re: 58 Evinrude Bigtwin 35

Thanks guys for the help.

F.R, that is the answer I was looking for. No oil out of the exaust. Must be the gasket. I'll let it be. Really don't want another project right now anyway. I can always wipe away a little oil.

 

[tashasdaddy]

Re: 58 Evinrude Bigtwin 35

i totally agree with F_R. but service the water pump with a water pump kit, not just the impeller. no need to burn it up. it's a 20 minute job.

 

[Trackbolt]

Re: 58 Evinrude Bigtwin 35

I bought entire pump kit. I also bought two coils and point sets at the same time. The old coils are not the origional coils. I installed new coils and points in 1982. It has had a new pump kit every three years or so up untill I stored it in 1997. Cheap insurance policy.

Thanks

Tony M.