Weird Spark Problem (Long Post)

[Thompy_04]

I've got a odd spark problem on my 1960 Johnson 18. I just changed all the points, condensors, and coils, but the spark seems to come and go. If I take all the parts out and check the point gap and replace all parts I can get spark. Then after running the motor for 3 mins, the spark just seems to disapear? The spark isn't getting to the top cylinder and I need to know what set of points and coil is going to that cylinder. Maybe I just mixed something up. The eccentric screw on the right set of points doesn't want to hold down the point, it wants to move back and forth thus changing the point gap. Maybe thats what is the matter. But in turn I have no idea how to keep it still. When I do get spark to both cylinders the motor runs good at idle but surges at high speed unless the primer ball is pumped. Classic fuel pump or carb float prob, but those parts have been ordered. Just need to get this stupid spark prob down, seems to happen every time.

 

[Joe Reeves]

Re: Weird Spark Problem (Long Post)

The coil closest to the front of the engine (Carburetor area) and the points connected to it are the top cylinder.<br /><br />The eccentric does not hold down the point base. The other larger screw is the retaining screw. If that larger screw does not tighten the point base securely, therein lies your problem.

 

[Thompy_04]

Re: Weird Spark Problem (Long Post)

Thanks for the quick reply Joe. I would guess this is what is causing the weird starting condition also. It will turn over and run for about 4 seconds with the choke on, then die. Turn choke off, and fuel drips out of carb throat. Could a bad float cause the fuel dripping out of the carb throat? 2 pulls with choke off starts right up, runs odd, cleans out, runs odd. Give it some throttle and she surges. Thanks for the help, will take a look at that.

 

[Thompy_04]

Re: Weird Spark Problem (Long Post)

Fixed all of the spark on this motor, dumb me didn't seal the coil to HT lead and it came loose. Ran reallllly rough at midrange, but hauled at WOT and idled really well. The float isn't new and is giving me some questions to think about. At WOT you can get it to run good for about a minuete, then it will bog and you will have to pump primer ball. Runs good and have to reapeat process. Sound like a bad float? Also my cam rattled itself loose and eventually fell off, could this cause the rough midrange and WOT probs? Any suggestions, almost there to having her TOTALLY ship shape.

 

[Paul Moir]

Re: Weird Spark Problem (Long Post)

By cam I take it you mean the one on the armature/magneto plate that drives the carburetor?<br />If so, if that's not set correctly then your midrange will suck. Have a look in the manual under synchronization (link&sync).<br /><br />The WOT problem sounds more like a fuel restriction or a weak fuel pump. Check fuel filter, hoses, tank pickup, etc.

 

[Thompy_04]

Re: Weird Spark Problem (Long Post)

Yes Paul that is the cam, and it came completely off.... And the bolts are somewhere at the bottoom of the Ohio River I believe they are nowhere to be found. Does anybody have ANY idea what size bolts or screws to use for this application. I also had the WOT problem in my 9.5 with the same tank and hoses to the motor but not as bad as with this motor. Could that be the prob? I've checked every little hose, filter, and pump and it all checks out ok. I'll try another tank and hoses, but is there any certain tank I should use. Been seeing alot of problems not using a Johnyrude tank or OMC hose. Without these OMC parts will it make a difference?

 

[Thompy_04]

Re: Weird Spark Problem (Long Post)

Anybody have any idea?

 

[Paul Moir]

Re: Weird Spark Problem (Long Post)

Oh, sorry Thompy - I missed your post in the clutter.<br />Seems to me that there were some bad bulb/hose combinations out for a while. Atwood comes to mind - mabey someone else can confirm. Try to borrow someone elses tank to confirm a problem. Also, the o-ring in the quick connector wears out pretty quick, and can let air in. Wiggle the connector to see if it helps.<br />Those screws are #10 24-tpi (threads per inch) 1/4" or 3/8" long.

 

[Thompy_04]

Re: Weird Spark Problem (Long Post)

Thanks for the suggestions Paul. Now I have thought the fuel pump could have gone bad, and if the tank and line isn't what is causing all of this could a float prob exist. When I choke the motor it doesn't run for more than 6 seconds then quits. When I take the choke off, gas drips out of the carb throat. Problem? Also I have a 1970 9.5 Johny and it has a two line fuel pump. Could I use this pump to see if the pump in the 1960 18 is bad? Two lines means crankcase pressure to work the pump, so is the part interchangeable? Just a thought. Thanks.

 

[Paul Moir]

Re: Weird Spark Problem (Long Post)

If the float was bad, the only thing it could do is stick or sink. If either of those things happened, then when you pumped the primer bulb fuel would flow out of the carb's throat. If the primer bulb is hardening up and there's no leaking, it's not a float problem.<br />I think the gas dripping is just from you overchoking the engine. Lots of gas gets sucked up when you have the choke on.<br />It seems to me that the 9.5 has the same pump as the 18hp, and you can just bolt it on and go. So sure, you can swap it. If the pump is the one that's smaller than the 18hp, then it won't supply enough gas at full throttle to the carb.

 

[Thompy_04]

Re: Weird Spark Problem (Long Post)

As far as the float, it takes alot of pumps to get pressure in the bulb. You can even hear a little hiss coming from the carb while you pump it prior to getting pressure. I have a new float ready to be installed. The pump on the 9.5 is the square pump, and the 18 has an odd shaped rectangle. I'll try anyway. Maybe a bad fuel filter even? Can this cause a WOT prob, with pumping the ball to get RPM's up again. Just trying to spend less money first before dumping money into a new fuel pump.

 

[Thompy_04]

Re: Weird Spark Problem (Long Post)

^Bump^