Lower Crank seal

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j_jtaylor

Seaman Apprentice
Joined
Mar 20, 2004
Messages
34
Gday again all, I have just been told that my 92 115 may need a new lower crankshaft seal as the drive shaft has fuel and oil residue on it, it has been running very rough at low rpm's does this sound fair??
 
R

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Lower Crank seal

hello<br /> its possible but its also possible that another problem is causing it to run rich and this causes a lot of waste oil in the exhaust.<br /> good luck and keep posting
 
J

j_jtaylor

Seaman Apprentice
Joined
Mar 20, 2004
Messages
34
Re: Lower Crank seal

Thanks again Rodbolt, it has been running extremely rich at idle and low RPM's. I will see how we go after we clean the carbys ect and take it from there. Is the lower seal normally really expensive to replace??
 
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jim dozier

Lieutenant Commander
Joined
Jan 8, 2003
Messages
1,970
Re: Lower Crank seal

Also check for a hole in the fuel pump diaphragm. A hole or tear will inject unmetered fuel directly into the intake port of the cylinder to which the fuel pump is connected causing that cylinder to run rich, particularly at idle and low rpms. Its hard on the cylinder walls too because the extra fuel (no oil) is washing the oil off the cylinder walls.
 
J

j_jtaylor

Seaman Apprentice
Joined
Mar 20, 2004
Messages
34
Re: Lower Crank seal

Well we have the motor in bits now and it turned out it needs a rebuild as the bottom piston has bits of needle bearings everywhere, appears one of the needle bearings expired, lucky it didnt go boom I suppose!!!
 
R

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Lower Crank seal

hello<br /> while its possible its also possible that the residue is due to another problem such as a leaking fuel pump causing it to run rich. as I am not there I cant say yes or no, I can say check everything else first and if you do remove the powerhead change the shift shaft as well.
 
J

j_jtaylor

Seaman Apprentice
Joined
Mar 20, 2004
Messages
34
Re: Lower Crank seal

The power head is now off, and somthing has damaged the bore, the head, and one piston. It also appears that there is some water damage on the bearing surfaces, it must have been rebuilt once before as its all a bit strange, I may just bin it and start again!!
 
J

j_jtaylor

Seaman Apprentice
Joined
Mar 20, 2004
Messages
34
Re: Lower Crank seal

A bit further into this we have also found that that the part of the block that covers the crank has a bloody great crack in it that looks like it has been hit by a rod at some stage, so far $4500 for the rebuild!!!<br />Must love boating!!!!!
 
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