57' 18 HP Fastwin

[55'Fleetwin7.5]

I picked up a motor today at a garage sale... Ugly lower unit with a rough weld job and several nicks in the prop... Owner "claims" it ran last summer.... We have heard that tune before too... Anyway, did not pay much for it and it came with a good two line tank (worth more than the asking price)... When you pull on the rope... nothing. won't move. She's not in gear... What's the best method for free-ing up a motor that may or may not be fully seized up? What are the diagnostic steps?

Thanks in advance<

Tom

 

[CharlieB]

Re: 57' 18 HP Fastwin

First step is pull the spark plugs and give the cyl's a health shot of Marvel oil or PB Blaster. Let them soak while you drop that gearcase off. You could have a locked up gearcase. Won't know til you try.

Good Luck!

 

[jspringator]

Re: 57' 18 HP Fastwin

PB Blaster took several days to free up my single cylinder Tohatsu.

 

[55'Fleetwin7.5]

Re: 57' 18 HP Fastwin

The fact that the prop spins in neutral means nothing, right? The lower unit looks like cr@p!..... If I unbolt it, will it drop? or is it one of those that need to start at the power head?.... If the gears are froze up, I will still use some marvel in the cylinders... don't you think?

 

[F_R]

Re: 57' 18 HP Fastwin

The fastwin lower unit comes off without removing the powerhead. Just remove the lower bolt from the shift rod connector, unbolt the lower unit and pull it down and away. The shift rod connector is behind the oval plate on the side of the housing about half way down.

 

[55'Fleetwin7.5]

Re: 57' 18 HP Fastwin

Finally I get a break! My other two are 55's 7.5hp. So, this will be a dream.
thanks

 

[55'Fleetwin7.5]

Re: 57' 18 HP Fastwin

I dropped the lower unit and the power head now turns... I opened up the gear case... There was a crack in the skeg and no oil at all in the case. The gears are covered in a light rust... Can these be rehabilitated? Can I clean them real well and soak them in oil?... The clutch dog looks pretty worn on one side. Any experience here guys? I am not sure if they are toast or not.

 

[jbjennings]

Re: 57' 18 HP Fastwin

Fleetwin,
From my experience, there's a 99% chance your lower unit is shot. If you can see some wear on one edge of each dog of the clutch then the clutch is bad, at least. If you look at the same edge of the gear ears they're probably worn as well, as in slightly rounded. This will cause it to slip out of gear at wide open or below, according to how bad they are. Considering that the lower unit already looks like stuff, I'd just get ready to find me a good used one. Check your compression now that the powerhead is free and see if it's worth putting a used lower unit on it. By the way, if you get your '57 18 running good, you probably won't like your 7.5 nearly as much. I have a '55 7.5, too, and although I do still love the little fellow, I don't use it very often because it's just a little too slow and I'm an impatient type of person.
Post some compression results on the powerhead, I'm curious.
Good luck,
JBJ

 

[samo_ott]

Re: 57' 18 HP Fastwin

Ha. I agree with JBJ, once you get the 18 going the 7.5's will be collecting dust!

Unfortunately, up here the LU's are harder to find then the powerheads... I find almost all power heads are in good shape and still usable. And this is for all the engines I have in the 5.5, 10 and 18's. LU's are dear. I have a lot of bottomless engines hanging around in my shed. So keep all the parts as spares and see if you can find a used one.

 

[wbeaton]

Re: 57' 18 HP Fastwin

Look for a lower unit from a 1955-57 10 hp or a 1955-1958 (possibly 1959) 15-18 hp. I'll have to look into that one.

 

[F_R]

Re: 57' 18 HP Fastwin

I could be wrong, but isn't the gear ratio different in the 10? Just thinking out loud.

 

[samo_ott]

Re: 57' 18 HP Fastwin

You can use the LU's from much later 18's. My '66 18hp interchanges with my 50's models... And the later ones I have seen, they look the same also... I bet into the 70's they will interchange... as well as the 20's and 25's MIGHT be the same... that's I'm not sure off, but my newly acquired '73 25hp LOOKS the same in the LU dept, but I have not tried it.

 

[wbeaton]

Re: 57' 18 HP Fastwin

I believe the 10 and 15 hp share the same lower unit. The difference is the prop pitch. I think the 18 hp shared the same lower unit until 1958 or 1960 when there was a change, but I'm not as sure about that one. I'm sure 1960-73 18 hp lower units are the same. I'll double check when I'm home tonight.

 

[wbeaton]

Re: 57' 18 HP Fastwin

Well I've just looked into this a little further and I'm no better off. The short answer is that my info is right depending on the source. However, you may be able to use a complete 18 hp lower unit from a motor as new as 1973.

My (1974) Johnson Common Parts Manual says the 1956-57 10 hp and the 1956-57 15-18 hp share the same gear set. However, the parts manuals I have for these motors comes up with different gears/gear sets. Suggesting that the 1955-1956 10-15 hp is not interchangeable with the 18 hp.

The manual further states changes in the 18 hp lower unit in 1958, 1960, 1962 and 1970. The entire assembly may interchange with the 1957, but the gears sets probably do not.

The Johnson manual is further backed up by my (1976) Evinrude Common Parts Manual, which says that the 1956-58 15-18 hp gear sets are the same. With a change during the 1959 model run.

This is the best info I can give. I'm not making any promises.