The Plugs in my boat motor

[alvinopry]

I have a 1995 50hp Johnson boat motor. The plugs run well when the motor starts and is cool. However, as it begins to warm up, it starts to miss. What could the problem be? (could it be the coil or power pack)?

 

[Hearseman]

Re: The Plugs in my boat motor

Tried new plugs???

 

[ob]

Re: The Plugs in my boat motor

Have you ruled out fuel delivery problem as the possible culprit? Need more info on your problem to advise.Does this problem occur when running at idle on the hose?Will the engine run in water at any speed without symptom occurring?

 

[boatmec04]

Re: The Plugs in my boat motor

Hi Sinsin<br />I'll Have to agree with COFFIN on this issue!!<br />What Type are you using??<br />I've Found that the best plugs to use on the water<br />anywhere are Champions.If I'm not mistaken that motor uses a Champion QL78YC or for extended idle<br />use QL82C.The plug are Gapped at 0.030 in.(0,8 mm).Hope this helps you.

 

[rickdb1boat]

Re: The Plugs in my boat motor

I agree with OB. Give us a little more info on what's going on with it. Especially how it runs on the water! It could be fuel or a fuel tank vent problem or possibly it is a powerpack problem. More info will allow us to advise tests to perform.Plugs usually foul at any temp! Recommended plugs are QL78YC gapped at .030. Try new ones anyway and while you're at it, check to see what condition they are in. Describe this in your next post. Another way to narrow it down, is when it misses when warm, shut it down right away and pull the plugs and see what they look like. If dry or white deposits, you are starved for fuel. If wet, you are to rich. Also, when it does this, pump up the bulb and see if it improves. You could also heat the powerpack with a hair dryer up close and see if that affects the running. Long shot, but who knows.

 

[AUGIDAWG]

Re: The Plugs in my boat motor

The QL82YC plugs will give you a better idle, but, be carefull.<br />I tried them last weekend. Fixed my trolling/fouling problem.<br />The motor ran great.<br />But, when I pulled them out to have a look, the porcilin insulators were pure white. If this was a four stroke, I would say that they were ok as far as heat range goes.<br />But, for a 2-stroke, they looked lean or too hot. When you are burning oil in your fuel, you should see some discoloration on the insulators if everything is correct. Light brown or tan is ok. But white means the engine is running "on the edge" of disaster.<br />I will keep them in my tool box in the boat incase I get stuck with a set of badly fouled plugs, or plan to troll all day.<br /><br />My 200 Ocean Runner engine is different than yours, but they run the same recommended plugs.