1972 20HP a few questions

[noppy]

Hi,
i havnt been on here for a while as ive been busy,
to remind you of where i started from and am now.

Boat: 14.5ft speedboat rather old, repaired inside and repainted and fitted

Engine: 1972 Johnson 20HP longshaft, replaced coil, redid points etc , replaced fuel filter cover, stripped and cleaned carb, new plugs, stripped and cleaned recoil, fitted stop button with cord, stripped and in the process of painting.

thats as far as ive got, at the moment im stuck, it starts first time give or take now but it idles fast and slightly irratically. The trigger plate slowly wobbles moving about 3 or 4 mm max, if i hold it still it idles much better

My questions are:
1) what can i do about the trigger plate?

2) how do i make it idle slower?


Thanks Gavan

 

[kbait]

Re: 1972 20HP a few questions

Sounds like one of the coils is rubbing on the flywheel magnet. Pull the flywheel and check to be sure the coils are even w/the plate they mount on facing the flywheel. If you loosen the 3 screws on the coil, you can move it around a bit, and set 'em even w the mount on the stator. You'll see what I mean when you look. That is probably accounting for the poor idle performance too. G'luck!

 

[noppy]

Re: 1972 20HP a few questions

Thanks
thats a pain i had the flywheel off literally 3 days ago to do the points if only id asked before i tightened it back down

the fun begins again

Thanks again il report back with what happens

 

[noppy]

Re: 1972 20HP a few questions

I did as you said and now it starts first time but it wont idle for more than a few seconds
on the bright side when it idled it idled slower

What could be making it not idle?
even when i increase the revs it still dies after a max of 10 seconds

 

[noppy]

Re: 1972 20HP a few questions

I took of the carb cleaned it rereadjusted the coils put it all back together and hey presto idles pretty damn good.

One thing still bothering me is that it only starts and idles when the second flap in the carb is slightly open. Why could this be?

 

[Daviet]

Re: 1972 20HP a few questions

You might want to try a link and sync to make sure everything is adjusted properly.

 

[noppy]

Re: 1972 20HP a few questions

whats a link and sync?
i aint very good with all the boaty terms

 

[Daviet]

Re: 1972 20HP a few questions

It is an adjustment procedure for all linkages on the engine, it duplicates factory settings. If you don't have a manual you probably can't do it.