spark plug gap

[bassone]

I have a 2001 Johnson 150hp "carb" it has champion plugs ql78yc i just went and got some ngk plugs, could someone tell me the gap for these ngk plugs, thanks!

 

[boobie]

Re: spark plug gap

.030 ". But you should be using Champions as the mtr was designed for them.

 

[bassone]

Re: spark plug gap

.030 ". But you should be using Champions as the mtr was designed for them.

thanks for the info, having problems with the plugs not lasting very long and the guy at our local boat shop said for me to give the ngk a try

 

[wired247]

Re: spark plug gap

Ive had no problems at all with the NGK BR7HS . If anything the Capacitive Discharge system used in the Johnson engines was an exercise in overkill. Only plugs Ive had problems with were the factory recommended Chamion UL77V.

 

[Tim Frank]

Re: spark plug gap

thanks for the info, having problems with the plugs not lasting very long and the guy at our local boat shop said for me to give the ngk a try

If the guy at the "local boat shop" told me to try a different plug than what the manufacturer recommended... instead of trying to find the reason the motor is eating plugs, I'd find a different "local boat shop"....:facepalm:

What did the plugs look like that "did not last very long". The plugs' appearance can tell you a lot.....if you look and listen.

 

[boobie]

Re: spark plug gap

If you're getting short plug life out of the Champions you've got some other problems.

 

[JB]

Re: spark plug gap

I see a lot of people talking about changing spark plugs. Don't they clean and regap them any more?? Is this part of the modern practice of "troubleshooting" by throwing hundreds of bux worth of new parts at an outboard in the hopes that it will magically start working right?

 

[boobie]

Re: spark plug gap

JB. The ones that just replace the plugs don't remember the old Champion spark plug cleaning machines. They worked real good if you went through the proper procedures. They could even test a plug to see how it would act under load. Same as an open air gap spark tester today. Dam, I miss those days.

 

[JB]

Re: spark plug gap

Thanks, boobie. Wow, what an expensive change.

 

[bassone]

Re: spark plug gap

If the guy at the "local boat shop" told me to try a different plug than what the manufacturer recommended... instead of trying to find the reason the motor is eating plugs, I'd find a different "local boat shop"....:facepalm:

What did the plugs look like that "did not last very long". The plugs' appearance can tell you a lot.....if you look and listen.

Thanks for the advice Tim! Tim i do have a very small miss during idle, took the plugs out and took one to the boat shop and thats when the guy told me its the junk plug, the champ plugs go bad all of the time! Most all of the plugs had a lot of black on them not much of the plug looked clean. I do need to try to find someone else to take it to but around here i dont have many to choice from. Any help would be great, the motor runs very strong when you put the gas to it, if i just idle around for a bit and give it gas it is a little sluggish at first but runs out ok, also at idle it may die and it seems harder to start at fisrt but once you start it once for the day it seems to start ok, hope this makes some since, Thanks!!!

 

[CharlieB]

Re: spark plug gap

A little troubleshooting goes a long way.

A simple compression test along with a spark gap test tells you a lot about the condition of your motor. When both tests confirm a healthy motor begin to dig into the fuel system as carbs DO get dirty, causing issues that can soon destroy an otherwise fine motor.

Clean carbs, be sure to order new carb rebuild kits, never re-use bowl gaskets, rebuild the fuel pump, replace all fuel hoses, adjust carb linkage and timing EXACTLY as spelled out in the FACTORY service manual.

 

[boobie]

Re: spark plug gap

JB. Most service stations and garages had them back in those days and you could take your plugs into them and have them cleaned for little or nothing.

 

[Tim Frank]

Re: spark plug gap

Thanks for the advice Tim! Tim i do have a very small miss during idle, took the plugs out and took one to the boat shop and thats when the guy told me its the junk plug, the champ plugs go bad all of the time! Most all of the plugs had a lot of black on them not much of the plug looked clean. I do need to try to find someone else to take it to but around here i dont have many to choice from. Any help would be great, the motor runs very strong when you put the gas to it, if i just idle around for a bit and give it gas it is a little sluggish at first but runs out ok, also at idle it may die and it seems harder to start at fisrt but once you start it once for the day it seems to start ok, hope this makes some since, Thanks!!!

My initial reaction to your description is that the slow speed mixture sounds too rich....and may be fouling the plugs.
Read more here http://www.bcchapel.org/pages/0003/pg11.htm for some explanation of "the colour code".

As JB and Boobie are suggesting, cleaning plugs is not difficult or all that unusual. if the plugs are being rendered u/s, burnt electrodes etc. that is a different issue and points to more serious problems.

If you are just fouling the plugs after prolonged idling....that is probably more of an inconvenience than anything, but could point at some deteriorating ignition components.
Systematic trouble shooting on that motor is not difficult and CharlieB has offered some good pointers already.
BTW, are those Champions surface gap plugs?

 

[JB]

Re: spark plug gap

JB. Most service stations and garages had them back in those days and you could take your plugs into them and have them cleaned for little or nothing.

I had my own plug cleaner/tester in the old days, boobie. I am just regularly shocked by the way people fix what ain't broke and don't know how or don't want to do some serious investigation of what is really wrong.

Look at post #11: Fix carbs, fuel pump and fuel lines on a guess that might fix what is really wrong. Only the compression test is diagnostic. I am not blaming CharlieB; He is just trying to get bassone back on the water.

We need to explain to these guys how to tell if a carb or fuel pump needs overhaul and save them big bux. Troubleshooting is becoming a lost art.

 

[CharlieB]

Re: spark plug gap

A little troubleshooting goes a long way.

A simple compression test along with a spark gap test tells you a lot about the condition of your motor. When both tests confirm a healthy motor begin to dig into the fuel system as carbs DO get dirty, causing issues that can soon destroy an otherwise fine motor.

Clean carbs, be sure to order new carb rebuild kits, never re-use bowl gaskets, rebuild the fuel pump, replace all fuel hoses, adjust carb linkage and timing EXACTLY as spelled out in the FACTORY service manual.

Of course if either test fails that issue must be corrected before proceeding any further.

 

[boobie]

Re: spark plug gap

JB, troubleshooting was the most fun of this whole game. It's after you found the prob, fixing it was the PITA. Do you remember the old Sun Test Equipment slogan?? "Test, Don't Guess". That sure was true.