Hotter spark plug?

[drbobp]

I have a 1996 Johnson Fast Strike 150 and I have disconnected my VRO. Saturday I was running and my overheat warning went off. I checked the water pressure (24 pounds) and the water coming out the pee-hole - it was fine. When I throttled back, the horn stopped. It ran fine for about 25 seconds and then shut itself off. I restarted it...it shut itself off. The engine was NOT hot. After trolling about 10 minutes and periodically cranking, I had an inspiration....check the fuel bulb. It was flat...I was out of gas in one tank. When I switched over it cranked right up but seemed like I had a fouled plug. The horn did not sound again.<br /><br />I came to work this morning and forgot to see what plug I need to get for replacements. Is it QL78YC (champion)? Since I'm mixing my oil, should I get a hotter running plug? Thanks!<br /><br />Bob

 

[papasage]

Re: Hotter spark plug?

i think that is a surface plug that is what my evinrude carry i use a QL77JC4 it is a 1979 evinrude . the surface gap will foul easier . especialey if you do a lot of idling . with the vro working i think it doesent put as much oil to the gas .had a plug chart but it has men updated and it didnt work . papasage

 

[Dhadley]

Re: Hotter spark plug?

The horn was the low fuel pressure warning (obviuosly). I wouldn't put any hotter plug in that motor. In fact I run cooler ones in my 60 degree,

 

[Dhadley]

Re: Hotter spark plug?

^

 

[seahorse5]

Re: Hotter spark plug?

Better give us the motor model number as the '96 and later motors use the SystemCheck warning lights with a 10 second horn.<br /><br />Earlier years had the continuous horn sound when a motor overheated. <br /><br />It sounds more like you had a fuel restriction, which can also cause lean running, piston damage, and higher oil consumption.<br /><br />The flat fuel pump reinforces the restriction problem. Check the complete system from the bulb all the way back to the fuel pickup tube.

 

[rodbolt]

Re: Hotter spark plug?

yep what they said.<br /> that is why these manufactures spent somuch time and effort to give audible AND visual indicators. had you eyeballed the system checklights it would have had the check engine lamplit. if you dont have the lights memorized for function now would be a good time. you will also need to test compression. with the VRO disconnected it did not over oil.<br /> my reccomendation is to service the VRO system like the manual says and replace the pump at 6 year intravels. hopefully no mechanical damage is done and it somehow fouled a plug. but it is time for a compression test at least

 

[drbobp]

Re: Hotter spark plug?

Thanks to all of you! I don't have the VRO installed any longer...I mix the oil in the gas. This is the first time the horn has sounded before the fuel ran out so I didn't think to switch tanks until I had REALLY run all the gas out. Duh! <br /><br />Lots of quick answers..but I guess I will go home and take out the old plugs to find what model I need. Thanks again!

 

[Dhadley]

Re: Hotter spark plug?

You can run the QL78YC as you mentioned and you can also us the QL77JC4 which is a tad cooler.

 

[drbobp]

Re: Hotter spark plug?

Dhadley,<br /> Why do you run the cooler plug? (Thanks for the numbers)