79 35hp Johnson stalls under load

[kirkpatrick]

I have the above motor, it ran great last year. I got it out about a week ago, it idled fine on the water hose. I took it to the boat ramp and launched. It idled fine out of the dock. As I opened it up it started missing and died. I tried to crank, it would turn over but not start. I checked the fuel bulb it was tight. I finally got it started, once again it idled fine. When I tried to get up on plane it missed a few time and died. Fuel bulb still tight. I finally got it back to the ramp. I thought the float was sticking.<br /> There was one thing that really didn't fit the theory of carb. problem. As I was cranking on the moter to start after it died, the instant I hit the electric choke button it fired, even before the butterfly could close.<br /> Went to the boat shop bought new carb. kit. Installed it, hooked up to water hose ran on hose just fine.<br />Took it back to the river. Same thing when I tried to open it up, it would miss a few times and die. (I also took along a timing light to check firing when it died) I hooked up the light, as I was cranking it was not firing. occasionally it would fire and the light idicated such. I got it recranked and idled bak to the ramp. <br />I am now convinced I have a firing problem, but it only shows up when the motor is under a load. It is very hard to restart once it has an episode like this, but when it does start it idles just fine. I am at a loss....please help<br /><br />Jeff

 

[WillyBWright]

Re: 79 35hp Johnson stalls under load

The trigger wires may be broken internally, or maybe they're worn thru and shorting. Either way, your problem might be showing up as you advance the throttle, and thus advance the timing. That movement may be causing the effect. That'd be my first guess.

 

[oldboat1]

Re: 79 35hp Johnson stalls under load

could simply be adjustment of the carb high speed needle. It sounds like you can start the motor at the dock. Have a friend accelerate while you adjust the needle -- too lean (clockwise) and the motor will cough and stall from lack of fuel. Too rich (counterclockwise) and the motor will stumble from too much fuel. The proper setting is midway between the two extremes.

 

[oldboat1]

Re: 79 35hp Johnson stalls under load

oops. reread your posting -- may need a carb adjustment, but the main problem is ignition if you are not getting consistent spark. <br /><br />apologies....

 

[G DANE]

Re: 79 35hp Johnson stalls under load

Hi There<br /><br />While iddling, try to wiggle with the wires where they leave the stator, just behind the wire terminals on the port side of motor seen from boat. The wires bend there when stator turns, and occationally an internally broken wire is seen. If they are, ignition will be cut out when stator starts to turn. The broken wire can be soldered. See if your kill wire is worn through insulation somewhere at cowl, I tried that and it was lying sparking under carb !