Correct Spark Plugs

[Pokertrampp]

I have a 1988 Johnson 120hp. It currently has NGK plugs installed, I was reading here that they prefer Champion Plugs. Can any ojne tell me the correct plugs to install? I have seen several threads about it but they all refer to V6 models, I have a V4 the closest I could fine was QL16V are these the correct plugs? also I have heard that the way you drive determins the plug, while i do some hi speed i also do some low speed so i am just comfused as to which plugs to use. thanks

 

[ezeke]

Re: Correct Spark Plugs

I've been running mine on Champion QL77JC4 plugs for 22 years with no problems.

Recently, some charts are showing the Champion QL78YC: http://continuouswave.com/whaler/reference/BRP/SparkPlugChart2008.pdf

The original owner's manuals and service manuals gave the QL78V and L78V surface gap plugs as alternatives to the QL77JC4 for sustained high speed use.

CDI recommends QL77JC4 (see service note at top of page): http://cdielectronics.com/downloads...linder 1988-2001 120-140 HP (Quick-Start).pdf

 

[marinemech1]

Re: Correct Spark Plugs

QL-16v where used to clear up some low speed issues....Latest recommended plug is Champion QL-78YC
Wayne

 

[Pokertrampp]

Re: Correct Spark Plugs

I went to the marina and the mechanic recommended QL77JC4, so I bought those for now and will see how they act. thanks

 

[marinemech1]

Re: Correct Spark Plugs

QL-77JC4 where the original recommended plugs so you should have no issues. QL-78YC are now the recommend plug (I think for longevity reasons).
Wayne

 

[Tim Frank]

Re: Correct Spark Plugs

QL-77JC4 where the original recommended plugs so you should have no issues. QL-78YC are now the recommend plug (I think for longevity reasons).
Wayne

Longevity of the plugs or the motor?

 

[seahorse5]

Re: Correct Spark Plugs

Longevity of the plugs or the motor?

The QL78YC plugs have an extended nose on them putting the spark arc deeper into the combustion chamber. That gives less fouling and better running at low speeds than the QL77JC4 plugs. OMC and Champion made the change back about 15 years ago or so.

 

[lineflyer9]

Re: Correct Spark Plugs

The QL78YC plugs have an extended nose on them putting the spark arc deeper into the combustion chamber. That gives less fouling and better running at low speeds than the QL77JC4 plugs. OMC and Champion made the change back about 15 years ago or so.

I have just put Champion L76V plugs in my Johnson 120 hp V4. Is it okay to run these in this engine? Has anybody run these plugs in this engine and what are your results?

 

[Daviet]

Re: Correct Spark Plugs

lineflyer9, you should start a new post rather than bringing up a two year old post.
I beleave the L76V is a surface gap plug, and can be replaced by the QL77JC4 for better low speed operation.

 

[lineflyer9]

Re: Correct Spark Plugs

lineflyer9, you should start a new post rather than bringing up a two year old post.
I beleave the L76V is a surface gap plug, and can be replaced by the QL77JC4 for better low speed operation.

Sorry, I had just joined iboats and I am new to boating & just wanted to make sure I had the right plugs for better low speed operation. Thank you for the information.