3Hp Johnson won't run without choke

[RPJS]

Model #JW18R<br />Serial # B65288<br />Can anyone help<br />I found the above motor when clearing out my farthers garage, I do not know how long it had been standing for but it must be several years.The motor was not seized when I found it but was fairly tight when turned over. I removed the plugs and filled the pots with WD40 and left to stand for 3 days then by very gentle movement of the flywheel I freed the motor off and it now turns over very smoothly. I have also removed the carb and fully cleaned and blown thru all jets etc. I removed the magneto plate and cleaned the points, the green insulation on the coils is cracked in places but I get a very good blue spark on both plugs. I do not have a compression tester but this seems to be OK when I turn the flywheel by hand.<br />The problem is that the motor will fire and run OK with the choke 3/4 closed however if I try to open the choke fully it just dies, this happens in all throtle positions.<br />Any sugestions please<br /><br />Many Thanks

 

[Paul Moir]

Re: 3Hp Johnson won't run without choke

RPJS - those coils will arc over as you pick up timing (speed up the motor). Put 'em on your repair to do list. Iboats sells them for around $17USD each (part number 18-5181).<br />Your JW-18 is a 1963 model, so it's fuel mix is 24:1 91 or better RON gas to TCW-3 rated outboard oil.<br />If the engine will only run with choke, the carb needs to be disasembled, cleaned and rebuilt with a new carb kit. You should try to get a carb kit from your local Bombardier dealer, since the OEM kits come with a replacement float. The old cork ones can get sodden with todays gasolines and sink.<br />Also, you need a new water pump impeller. It's less than $10 and it should be replaced every couple seasons, regardless of use.<br />You need a repair manual. If you don't want to order one from Iboats, borrow one from your local library. <br /><br />That's a really sweet outboard if you get it running right. <br /> <br />Excellent 3hp tune up article, click here.<br />PS - two things about that outboard -<br />1) There's a fuel filter just about the shutoff petcock up inside the tank. Remove the large brass nut to find it. Make sure you have adaquate fuel flow to the carb.<br />2) The screen an intake silencer must be in place for the outboard to run right.

 

[DJ]

Re: 3Hp Johnson won't run without choke

I agree completely with Paul.<br /><br />Most likely, the cork float has sunk. The new kit will have a new one.<br /><br />The coils can also start breaking down, so be prepared to service those too.

 

[RPJS]

Re: 3Hp Johnson won't run without choke

Thanks for your help, I'll get the parts ordered.

 

[Bass Runner]

Re: 3Hp Johnson won't run without choke

Sounds like the low speed jet has some varnish in it, my 33hp is bad about that, I just pull the needle out and shoot a little carb cleaner in there and let it set then blow it out with air, works every time on my motor.

 

[Paul Moir]

Re: 3Hp Johnson won't run without choke

That's a great idea Bass Runner! You get a nice straight shot directly into the top of the idle orifaces. No fussing about with core plugs.