1966 33hp Evinrude SKi-Twin

1966 Evinrude 33HP Ski-Twin
1966 MirroCraft 14' Ski 'N Troll

I bought the boat and motor 5 years ago with oil seals leaking, no trailer, 3 years ago bought and rebuild trailer, no tow vehicle. Bought a truck last month, I talked to a local mechanic who said he could service my outboard but it would take a few weeks, 3 weeks later he calls and says the dealer still had no even ordered parts. I said forget it, he was honest and straight forward with me the whole time and do not fault him. I took the boat on the water anyway, It started right up as know how to store engines, I went a few feet and checked water was peeing out the back, which is did not do in a pail. I tested it for about 10 minuites then back on to the trailer. I changed the plugs and went out again last week, spent 20 minutes on the water the motor runs flawlessly no clunks, grinding of any kind of odd noises during the entire throttle range just a nice whine of the engine running...the boat planes out quickly and response nicely. I checked the gear fluid milkly which was no suprise, so I changed it out.

I am going to try and fix the motor myself, I order parts online here.
Seal kit, impeller, carb kit, tune up kit. I probally do not need it all, but i fgured pay shipping once.

My plan is to this season replace the leaking seals, Impeller this season. The carb and tune kit can wait until either the off season or next spring or when ever


I have done a lot of research and found pictures of what i need it seem like it should be no problem to change the impeller and oil seal, but i ahve never had one apart before. Any tips?



Thanks

Re: 1966 33hp Evinrude SKi-Twin

There are many threads on here about resealing the 50s 60s OMCS. It is a fairly straightforward job, we can help talk you through it. You will need some 3M 847 sealer, a seal puller, and a tool for removing the shift rod bushing. You can fabricate one yourself, or F_R on this forum sells them. They are of high quality.

Frank's Tools

Re: 1966 33hp Evinrude SKi-Twin

Hi gasch. I used to have a '66 33 Johnson myself. Here are some great all around tune up links for your new "Big Twin" with lots of pics and explanations. Generally speaking, these old motors are pretty straight forward. You'll want to run 50:1 mix, with Champion J6C plugs along with 80-90w hypoid, outboard gear oil in the lower unit.

Reviving a Vintage Big Twin - Part 1

Columns - Obsolete Outboards

Columns - Obsolete Outboards

Re: 1966 33hp Evinrude SKi-Twin

Thanks for the help and link guys I have been looking for 2 weeks.

I got the mix just bit more than then 50:1, did not look like enough.
I NGK B6S in there runs like a top.

I would have put outboard gear in it......thanks.

Re: 1966 33hp Evinrude SKi-Twin

If it ain't broke, don't fix it. Leaking seal may just be the crush washers on the drain and vent bolts. Drain the lower unit, fill with fresh oil, replace the bolts with new crush washers, and check the oil after a few runs.

I bought a 1957 Lark 6 years ago, replaced the impeller and she started right up. I figured I should replace the points, clean the carb, etc. But she ran so good!! That was 6 years ago and I've basically done nothing to the motor except some new plugs. Every Spring I say to myself "you ought to at least clean/rebuild the carb" - but she always starts right up and runs great! I feel guilty, but like I said, if it ain't broke, don't fix it.

Re: 1966 33hp Evinrude SKi-Twin

Part of me agrees with you "Lindy46" but ...the outboard has not seen the water since in over 10 years........
I changed the gear oil and tilted the outboard up, oil leaking out the side plate "water bypass" I think it's called.
I order the 4 items because of the low cost under $20 each, $100 ship to my door. if I have to go to a dealer to get them....I know the price will be triple that.

There is water coming out the hole so it is no hurry for the impeller at least today.
When I changed out the oil last week, when I tilted the outboard oil came out the plate on the side bypass plate I thinks is called, I can just change the gear oil after every use until I want to tear apart the lower end.

Re: 1966 33hp Evinrude SKi-Twin

I looked up into the "what ever" with a flashlight seen water tube, shift rod, drive shaft, water pump housing. no sign of any oil, no that it could be that simple. Drained and refilled again, I thought I heard an air sound coming from the upper part of the gear casing. First thought upper seals.....Bad thought cracked case some where in there.

Re: 1966 33hp Evinrude SKi-Twin

Got my parts in, Delivered to my door about a hour ago.
Now all I need to do is to install the seals and impeller.

Maybe I will tackle that this week yet....Next week is out I am going camping in Algonquin Park with my nephew.
I will report back when I am done and up date how big of sledge hammer I needed...lol

Re: 1966 33hp Evinrude SKi-Twin

Well it's done and sealed once again, I will test tomorrow.

Went to my Brother in-laws and we tore into it. First problem we dropped the shift linkage screw down into the housing , we retired it later.
too out the bolts on the side and slid the lower end out and off. Too k the metal water pump housing off, the impeller the plate and the new seal under that was loose not seated, That's where it was leaking. Took the drive shaft out flipped it over that's when the fun started a hour later we final got the screws/bolts out. They were so tight too tight it took 2 of us to press on the screw driver and a pair of pliers the get them loose. We replaced the seals put it all back together, sealant in place new impeller even thought the old one looked brand new. Put the lower unit in place bolted it up.......guess what we forgot.....yup the tube was not in place in the water pump housing. SO we had to drop it again. It all went back together properly the second time. It pays to look it seems to shift nice and clean still. Could not test as a storm was on the way, but I am sure that the leak was the seal at the top of the drive shaft under the water pump plate not in place.

Re: 1966 33hp Evinrude SKi-Twin

Awesome! Sounds like you found and fixed the offending seal. Keep us posted!

Re: 1966 33hp Evinrude SKi-Twin

Excellent old motor you have there. I recently serviced a Johnson version for a fellow and it was a nice runner. These are based on the old '57 Big Twins.Look at the cylinder head, you'll see that there are a lot of castings on it, used on the '57 motors. They just removed certain things that were in the castings, for things that were not used on the 33's, like the compression relief valves. Funny thing is, you'll still see the mounting bosses for the release lever that opened the compression release valves.