How to time a 1966 20HP Johnson Seahorse

[zdurst]

Hey,

I have a 1966 20HP Johnson Seahorse and I have done a lot of work to get it running. Now I think the only thing left to do is time it right. Can someone help me out here.

I have tried to time it myself and on the cam that is attached to the crank there is a spot that says TOP^, So at the arrow is where I set the gaps to .020. There are two pistons.

Any help would be great.

Zac

 

[F_R]

Re: How to time a 1966 20HP Johnson Seahorse

That is all there is to do. Gap the points when the rubbing block is aligned with "top". Then turn crank till "top is aligned with the other set of points and gap them. That's it.

When you reinstall the flywheel, make sure the shaft and flywheel tapers are clean and dry and use a torque wrench to tighten the nut to 40-45 ft/lbs. This is important!!!!!

 

[zdurst]

Re: How to time a 1966 20HP Johnson Seahorse

Hey,

That is what I did but my engine is still running really rough. It has a really hard time reving up to full throttle. I have a fixed high speed needle. I have taked the carb off and cleaned it throughly.

Can you think of anything else I might be doing wrong?

Thanks,

Zac

 

[samo_ott]

Re: How to time a 1966 20HP Johnson Seahorse

Did you remove and clean behind the fixed high speed jet? And do you have a good spark on both cylinders? I have the same '66 J20 but just got it and have not worked on it yet.

 

[jbjennings]

Re: How to time a 1966 20HP Johnson Seahorse

How I hate those fixed High speed jet carbs!!! You have to soak it, soak it some more, pray over it, soak it again, etc. I despise working on those things. I love my adjustablem slow and high speed carbs. That definitely sounds like the problem like SamOTT said. Did you have any problem getting the high speed orifice out??? I always do even though I use my ground-down screwdriver that fits good. Seems like they're always froze up, too. I find it's better to just soak the heck out of it and use some wire to clean the orifice while it's still in.
Good luck,
JBJ

 

[samo_ott]

Re: How to time a 1966 20HP Johnson Seahorse

No kidding eh. A nice adjustable high speed jet is the way to go... And magnetos... Dang, they don't make em like they used to... sigh...

 

[zdurst]

Re: How to time a 1966 20HP Johnson Seahorse

Hey,

Thanks for the replies. I cant remember if I took it off when I cleaned it. I am going to try that tonight and see if that get it movin. Ohh ya, when I remove it I have to remove the nut holding it in and then will the high speed jet just come out or is it threaded?

Thanks again,

Zac

 

[jbjennings]

Re: How to time a 1966 20HP Johnson Seahorse

Zac,
DO NOT try to remove that high speed orifice unless you have made yourself or bought the proper tool!!!!!!! You WILL mess it up! It's made of brass and is pretty soft and guaranteed to break without the proper tool---and you'll probably find it frozen and even the proper tool won't work. I advise soaking it again, taking a small wire and really cleaning the orifice with it without scratching it, and trying it again. This is just my opinion and it's not based on a huge amount of experience. Maybe F-R will tell you the truly best way to do it. I hope so because I could use some pointers myself.
JBJ

 

[captk]

Re: How to time a 1966 20HP Johnson Seahorse

Did you adjust the pick up timing?

 

[zdurst]

Re: How to time a 1966 20HP Johnson Seahorse

Thanks JBJ,

I don't know what the pick up timing is? If you could explain this to me I can tell you if I have tried that.

Thanks,

Zac

 

[F_R]

Re: How to time a 1966 20HP Johnson Seahorse

You mean the throttle pick-up, right? The slop in the link should be taken up as the marks on the cam align with the roller, and the carb butterfly will just barely start to open as you go beyond that point.

I make those screwdrivers but can't offer to sell them here, according to the rules.