4hp Mercury crank counterweight removal

[Paul Moir]

I'm trying to replace the lower crankshaft seal on a mercury 4hp outboard (2 cylinder ~1980 I think, Serial #7154897, No Model #). Unfortunetly, there's<br />a counterweight hung off the crankshaft just below the seal, directly above the splines. I have tried _everything_ to pull the blasted thing off, but it won't budge. Am I missing something big here, or should I cut it off and try to find a new one? Thanks kindly for any help!

 

[Bear]

Re: 4hp Mercury crank counterweight removal

Do you have a manual?<br /><br />Can't see a counterweight here:<br /> http://www.dolleroffshore.com/parts.cfm?c=btp&m=1&pn=436&r=3555 <br />More parts:<br /> http://www.dolleroffshore.com/parts.cfm?c=bt&m=1&pn=436&bn=673

 

[Paul Moir]

Re: 4hp Mercury crank counterweight removal

This is actually a 4hp, 2-cyl 2-stroke motor, not a 40. Thanks for the site though. It doesn't look like any of the 3s, 4s, 5s, 6s, or 8s listed there (or the 40. I haven't gotten a manual yet. Also, this is one of those integrated fuel tank motors, and there's a plugged (threaded) hole in the bottom crankcase chamber. Is this for adding a fuel pump for an external fuel tank? It currently seems to be gravity fed.<br />Thanks again!

 

[Bear]

Re: 4hp Mercury crank counterweight removal

Sorry, my mistake.<br />These are the serialnumbers<br />40 (4,0) 9075839 - 9141798 1976 2 cyl - gnat <br />40 (4,0) 9141799 - 9172805 1977 2 cyl - gnat <br />40 (4,0) 9172806 - 1978 2 cyl - gnat <br />4 5589202 - (USA) 1980/1981 2 cyl <br /><br />As you can see the model says 40 for the two cylinder 4 hp model 1976-78. Your serial number match the 40 hp model. As was sure I was right untill I just saw the start motor link <br />I had a 402 model myself some years ago (40 hp 2 cyl, not 402 hp). Ever seen the 350, 500, 650, 800... models? Well, I was wrong.<br /><br />I think you are right about the fuel pump and gravity fed. (Actually I'm sure for what it's worth )

 

[Paul Moir]

Re: 4hp Mercury crank counterweight removal

Aha! I think it must be the 2 cyl gnat, '80 or '81. It turns out I've got a (Suprise!) Canadian Serial # which turnes into a 5589202- American serial #. Why couldn't Merc just use model numbers? The part I'm trying to remove seems to be the Shaft coupling from the site you sent me ( Merc Gnat Con Rod )<br />It doesn't look exactly like that, but it's pretty close. It seems to be joined by either splines or threads but, unfortunetly, I can't quite make it out. Looks like I've been trying to pull the wrong part off!! <br />Thanks again! Your reply was actually quite helpful after all!

 

[Paul Moir]

Re: 4hp Mercury crank counterweight removal

Splines they were! Finally got the blasted thing off. Thanks again!

 

[Bear]

Re: 4hp Mercury crank counterweight removal

That site can be helpful sometimes. <br />I'm glad it worked out for you and I hope you get it running soon.