Replacing the internal crankshaft seal (1of 3)

hooyah

Cadet
Joined
Apr 21, 2012
Messages
25
I took apart my port (Force 125) engine and discovered a broken crank seal. I ordered a new one and plan on putting it on. Does anyone have any advice on how to proceed without breaking it while trying to install it?
 

BobList

Petty Officer 2nd Class
Joined
May 20, 2010
Messages
135
Re: Replacing the internal crankshaft seal (1of 3)

start it evenly, tap around and around the new seal with a flat tipped punch ( or a SEAL installer, if you have access to one) work around and arond the seal.... no hard hits. If you gt it started straight, go down as far as the old seal, or until the taps feel "solid"..ie: no more movement
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: Replacing the internal crankshaft seal (1of 3)

Wrong type of seal, Bob!

The seal is a flat spring steel, permanently bent into a circle. When installed it will have a small gap like a piston ring. You MUST lift the crank to install it. Slip it in between the roller bearing and the seal land, then spread it over the land and into the groove. You can also simply slip it over the groove. If you remove the rod ends and lift the crank high enough, it will bend enough without breaking. The gap should be about centered on the semi-circular seal area.. do not allow it to be near the crankcase split line. Push them down as far as possible before installing the block front half.

However, be extremely careful when re-seating the crankshaft. This is a painstaking process as the four bottom bearings are pinned to the block and you need to seat each one, in order, from the top down. Place the crank onto the block with the bearings in the approximately correct position. Then slightly wiggle the bearing until you find the pin and it seats in the hole in the bearing shell.

While doing this you must be very careful to ensure that the crank seals stay in their grooves. Try and force the crank down with a misplaced seal and the seal will surely break.
 

BobList

Petty Officer 2nd Class
Joined
May 20, 2010
Messages
135
Re: Replacing the internal crankshaft seal (1of 3)

oh, ok! I even looked at the pics on ********** before I responded!!.. damn automotive training!! Thanks for calling that one out, Frank!!!

Bob
 

hooyah

Cadet
Joined
Apr 21, 2012
Messages
25
Re: Replacing the internal crankshaft seal (1of 3)

Thanks Frank, and Bob. I wish it were just a regular seal. By the way, Frank. Remember that piston pin I asked you about in June? I ended up buying a small 6 ton hydraulic press for 50 bucks new, and replaced the piston myself saving anywhere from 100-200 buckaroonies. I am waiting on some oversized rings to come in then I'll be reassembling this one. I hope this broken mechanical seal and the old lower seal is why I was getting so much unburnt fuel and black oil in my exhaust and all over my lower leg and transom.
 

jason32038

Chief Petty Officer
Joined
May 25, 2009
Messages
555
Re: Replacing the internal crankshaft seal (1of 3)

could help your excess fuel oil issue hoo depending on which one is broken..but the main purpose of those 3 "seals" are to keep crankcase pressure from escaping from one crankcase "section" to another. your engine will run a little better but I feel your excess oil fuel leak issue lies elsewhere.
 

hooyah

Cadet
Joined
Apr 21, 2012
Messages
25
Re: Replacing the internal crankshaft seal (1of 3)

Hopefully it was the lower seal.
 

hooyah

Cadet
Joined
Apr 21, 2012
Messages
25
Re: Replacing the internal crankshaft seal (1of 3)

Hey Jason and Frank, I did find another problem which could be contributing to that excessive fuel consumption. The cylinder drains were clogged and the screens were totally missing. I replaced the drain plates and now the engines are both back together awaiting a compression check followed by a start-up test.
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,909
Re: Replacing the internal crankshaft seal (1of 3)

Hey Jason and Frank, I did find another problem which could be contributing to that excessive fuel consumption. The cylinder drains were clogged and the screens were totally missing. I replaced the drain plates and now the engines are both back together awaiting a compression check followed by a start-up test.

Can you post pics of those drain plates you are referring to? Are you talking about the fuel-recirc system?
 

hooyah

Cadet
Joined
Apr 21, 2012
Messages
25
Re: Replacing the internal crankshaft seal (1of 3)

Here's what I'm talking about.IMG_0063.jpg
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,909
Re: Replacing the internal crankshaft seal (1of 3)

Oh yes, these are parts of the fuel recirc system.
 
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