Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

[northernmerc]

This is on a 2001 30 hp Johnson 2 stroke. It has electric start, which is a good thing as it does not like to start when cold. It has to spin quite a lot, with both the key pushed in (to activate enrichment) and the throttle lever raised, before it will start.

The other day, we were fishing, trolling for northern pike. It idled OK for about half a mile and then coughed and stalled. The Johnson would not restart. It's a good thing that we had the little Merc kicker on the boat, so we used that most of the afternoon.

After sitting for a couple of hours, the Johnson again started. It seemed to be flooded and I suspected that the spark plugs were fouled. I revved it a bit to clean out the cylinders and clear fouling, and then took it for a full throttle spin. It ran fine as long as we kept moving at a brisk speed. But again, after a minute or less of idling, it quit and would not restart. I tried all positions of the throttle and with and without enrichment. Nothing helped.

Later, I pulled the plugs. They were wet with gas, although they didn't look fouled or dirty. The plugs only have a few hours on them. I'm going to put new plugs in and use a fresh tank of gas next time out. Hopefully it will start and run.

The Johnson 30 has NGK BR7HS plugs in it. Is that the correct plug? I'm also wondering if a hotter plug might work better. Is a BR6HS a slightly hotter plug? Any other ideas for a better spark plug for this?

Also, any suggestions for improving the starting and low speed operation?

Thanks in advance for any help with this.

 

[DJ]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

Trash the NGK's and install OEM Champions. OMC's and NGK's do not play nice together.

 

[northernmerc]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

Trash the NGK's and install OEM Champions. OMC's and NGK's do not play nice together.

Thank you for that. Any idea what the correct Champion plug is for this engine? And am I better off running a hotter plug or a colder plug; we troll quite a bit at lower speeds.

 

[cr2k]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

You might go slightly hotter for your low speed operation, but I would not go too much hotter. And don't use the snake oil plugs i.e. Split fire or any others.

While I feel that NGK is a far superior plug to Champion; OMC outboards use Champions and don't run well on other plugs.

 

[northernmerc]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

Well, that's two votes for Champions. Any idea what the regular plug # is and the # for one plug hotter? Thanks.

 

[levi_tsk]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

champions or nothing for OMC's bro save the japanese plugs for the japanese motors....

check championsparkplugs.com OR call your nearest worst marine... QL82C is the proper one if you have a stereo or something electronic on the boat if not id run L82C instead same heat range but the "Q" indicates a resistor plug and this lowers radio interference from the magneto system...

 

[levi_tsk]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

and stick with the recomended heat range if your gonna do any full throttle runs... unless of course you like burnt pistons

 

[jasper60103]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

Well, that's two votes for Champions. Any idea what the regular plug # is and the # for one plug hotter? Thanks.

See Champion spark plug chart...

http://forums.iboats.com/showthread.php?t=403854&highlight=spark+plug+chart

 

[northernmerc]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

I looked at the charts. The Champion site says to use the L82C. The other chart lists three Champion plugs for this engine: QL82C, QL77JC4, and L78V.

Is the L82C the same thing as a QL82C? And how about the other numbers on that second chart?

 

[jasper60103]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

I looked at the charts. The Champion site says to use the L82C. The other chart lists three Champion plugs for this engine: QL82C, QL77JC4, and L78V.

Is the L82C the same thing as a QL82C? And how about the other numbers on that second chart?

The Q-type plugs are recommended for CDI.

From the champion website...
"Outboard marine Capacitive Discharge Ignition systems (CDI) such as used on some Johnson and Evinrude marine engines require a special inductive type resistor spark plug (such as a Champion Q-type). This is because these type of ignitions systems produces less voltage; use of non-inductive type plugs can cause misfires and poor performance."

 

[northernmerc]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

The Q-type plugs are recommended for CDI.

From the champion website...
"Outboard marine Capacitive Discharge Ignition systems (CDI) such as used on some Johnson and Evinrude marine engines require a special inductive type resistor spark plug (such as a Champion Q-type). This is because these type of ignitions systems produces less voltage; use of non-inductive type plugs can cause misfires and poor performance."

Next question: does the 2001 Johnson 30 hp use a CDI system?

 

[northernmerc]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

Next question: does the 2001 Johnson 30 hp use a CDI system?

Either this is a really stupid question (most likely) or a really difficult question (less likely). I've heard that the newer outboards have gone away from the CDI systems and just want to make sure that I get the right plugs for this engine. What I'm wondering is: do I buy the QL82C plugs or the L82C plugs - or are they the same thing?

 

[jasper60103]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

Either this is a really stupid question (most likely) or a really difficult question (less likely). I've heard that the newer outboards have gone away from the CDI systems and just want to make sure that I get the right plugs for this engine. What I'm wondering is: do I buy the QL82C plugs or the L82C plugs - or are they the same thing?

Yes, your 30 hp motor has a CDI system. Therefore, go with the Q-type plug. I've used QL82C and QL77JC4 without any problems.

 

[northernmerc]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

Thank you Jasper. Can you (or someone else) tell me what the difference is between the QL82C and QL77JC4? Or are they the same thing?

 

[jasper60103]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

Thank you Jasper. Can you (or someone else) tell me what the difference is between the QL82C and QL77JC4? Or are they the same thing?

I'm no expert, but QL82C is a hotter plug. I'm not sure which is best, but I heard if you're having problems with fouling plugs, go one hotter. That said, I would probably choose the QL77JC4 unless I had fouling problems.

edit: I re-read your post and since you indicated cold starting problems, you may want to review the Cold Starting Procedure in the Top Secret Files (see link below). Hopefully, this helps as well. Let us know how it turns out.

http://forums.iboats.com/showthread.php?t=225510

 

[northernmerc]

Re: Tuning advice needed, and what sparkplug will work best for my 30 hp Johnson?

Jasper, Thanks for that link to the starting procedures. I'm hoping that changing to Champion plugs will make a big difference. As I said in my original post, I'm glad this thing has electric start. I can't imagine having to start it with a pull cord; one's arm would wear out first.