POINTS AND PLUG SETTINGS

[DAVID BRUCE]

What settings for spark plugs and ignition circuit breaker points on 4HP Johnson Seahorse of 73 vintage. I have been told 15 for plugs and 20-25 for points. Any comments, the engine will not accelerate and runs rough.

 

[bubbakat]

Re: POINTS AND PLUG SETTINGS

Points set at 20 and the plugs at 30<br /><br />Champion plugs J6C<br /><br />It should be written on top of the fly wheel the points setting.

 

[seahorse5]

Re: POINTS AND PLUG SETTINGS

set brand new points to .022" to allow the cam follower to "seat in". Used points .020".

 

[Paul Moir]

Re: POINTS AND PLUG SETTINGS

Make sure you can draw a 1cm long spark off each plug. If one of the ignition coils has cracks in it's insulation, you'll have to replace it. Fortunately, new ones are cheap and easy to get. PS Point gap 0.5mm, plug gap 0.75mm if you're unfamiliar with common American unit abreviations.

 

[DAVID BRUCE]

Re: POINTS AND PLUG SETTINGS

Thanks guys,<br />Paul, can cracks in the insulation be filled,<br />and if so with what?.

 

[Paul Moir]

Re: POINTS AND PLUG SETTINGS

I tried that once (RTV silicone is ideal), and it didn't work out because moisture was trapped in the coil.<br />The Sierra imatation coil sells for about $15 US dollars each (18-5181). I like them better then the manufacturer's coils. It's just easier to replace them than to try to fix them.<br /><br />Iboats sells these coils but I don't think they export outside the US. There are plenty who do though. It might makes more sense to buy them locally. I see informar.be in Belgium carries them, and poortwatersport.nl has them for 27 EU$ each.

 

[DAVID BRUCE]

Re: POINTS AND PLUG SETTINGS

Thanks again Paul, I am going to strip down the top end and have a close look at the coils.<br />At the price you mentioned it may be worth replacing them.<br />By the way what is RTV silicone?<br /><br />Cheers,<br /><br />David

 

[Paul Moir]

Re: POINTS AND PLUG SETTINGS

RTV - Room Temperature Vulcanizing Silicone. This is basically any silicone caulk for the bathroom or windows that gets hard (well, rubbery) when exposed to air. It is an excellent high voltage insulator.<br /><br />I *hope* that explains it. Good luck!

 

[DAVID BRUCE]

Re: POINTS AND PLUG SETTINGS

Thanks again Paul! I will try it and let you know<br /><br />Over and out<br /><br />David

 

[DAVID BRUCE]

Re: POINTS AND PLUG SETTINGS

Woops,<br /><br />Paul one other small thing. I've taken off the flywheel and found some small cracks in the insulation as you mentioned, I filled them with the caulking and have reset the points to .5mm. The problem is where is the speed control lever to set the advance? With the speed control at stop or start or fast going left to right? Obviously this affects the advance of the ignition. I have done it at the start position but have not remounted yet with points set at tdc on the drive shaft. Maybe this is not clear to you. I can take some shots and put a page on my website if that would help.<br />Sorry to be such a bother.<br /><br />All the best<br /> David

 

[Paul Moir]

Re: POINTS AND PLUG SETTINGS

I've got my '72 4hp about 5m from my computer, so we should be all right. <br />The points should be adjusted to open .5mm maximum. That is, when the "rubbing blocks" on the points are touching the highest point on the cam that fits on the crank (drive) shaft. This is easily found since the key that indexes the flywheel is at the highest point on the cam.<br />Other than that, it does not matter where the the throttle is set. <br />I hope that comes through clear!

 

[DAVID BRUCE]

Re: POINTS AND PLUG SETTINGS

Hi Paul,<br /><br />I set the points when the mark /top/ on the drive shaft cam was centralised for each set of points so it should be OK. I will try it out tomorrow (monday). You will probably be in dreamland i.e. still in bed so I will leave you a message. Hope that the insultion repair will work, if not I will try your suggestions for Belgium and maybe in France. We are in Brittany near the town Lorient.<br /><br />Thanks again for your help!<br /><br />David <br /><br />PS Its almost dinner time here 19h 10

 

[DAVID BRUCE]

Re: POINTS AND PLUG SETTINGS

Hi Paul<br /><br />Sucess, the motor started on 3rd pull in a tank and ran up to high revs then back to idle OK.<br />Restarted 3 or 4 times with no problem.I will be doing sea trials tomorrow (tuesday).<br /><br />I will keep you posted<br /><br />-----great

 

[Paul Moir]

Re: POINTS AND PLUG SETTINGS

Good to hear it! Those are great little engines.

 

[DAVID BRUCE]

Re: POINTS AND PLUG SETTINGS

Paul,<br />As I said I 'm keeping you up to date. Sea trials completed yesterday. - Unfortunately after having run quite well, a bit of seaweed blocked the only water entry hole on the LU. I did'nt notice it for a while. Then the engine ran rough and conked out. It must have overheated. I have stripped it down again and I'm getting no spark on the upper plug( plug black and oily other clean and dry). Having caulked the coils, I was wondering if the condenser has given up the ghost. Is there any means of testing before replacement?<br /> I have a volt/amp/ohm-meter but I am not sure what to look for. I know that replacing the whole sheebang will not cost a fortune, but I am a bit of a stickler about changing parts when it is not necessary. (most garage people do this all the time for cars). Once bitten etc. Any comment?<br /><br />David

 

[Paul Moir]

Re: POINTS AND PLUG SETTINGS

I had the same thing happen a couple years ago. It was an unusually large peice of kelp. I had replaced the impeller about 2 weeks before.<br /><br />The condensors are seldom a problem, and easily tested by swapping them. If it doesn't kill spark on the bottom cylinder, it must be good. Try cleaning and regapping the points. If spark doesn't return, and the plug wires are good, then the coil is almost definitely the problem. You can try swapping it too if you want.<br /><br />Also, it's possible some of the wiring contacted the flywheel and the insulation got rubbed off. It needs to be tucked in really well.<br /><br />I hope some of that helps you out!

 

[DAVID BRUCE]

Re: POINTS AND PLUG SETTINGS

Thanks Paul I'll try out by swapping<br /><br />All the best<br /><br />David