Spark plug numbers?

Gary H NC

Gary H NC

Fleet Admiral
Joined
Dec 1, 2005
Messages
8,972
Was going to get new plugs for my 1981,175HP Johnson. My OEM service manual calls for UL77V,the plugs that are in it now are QUL77V. What is the difference?
 
F

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: Spark plug numbers?

The U/Q L77V is a surface gap isn't it? Sort of a good idea that didn't work out too well. Check for a more up-to-date list. I suspect the current reccommendation is for QL77JC4 gapped at .030" Somebody will probably come along here soon to confirm that.
 
E

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: Spark plug numbers?

To the best of my knowledge, that is the right progression of Champion plugs. The QL16V was also listed as a secondary, but all were V or surface gap plugs. The chart that I rely on is the most up-to-date public list that I have found and was formulated by respected industry technicians:

http://www.boatsetup.com/SparkPlugChart.pdf
 
A

andrewdennis

Recruit
Joined
Mar 20, 2007
Messages
5
Re: Spark plug numbers?

Along the same lines.... I was told by a semi-reliable source to run the surface gap plugs in my 1976 rude 65, as the standard (don't know what else to call them) foul out too quickly. Is this true, or is there something sneaking about in the motor I need to be looking for??
 
E

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: Spark plug numbers?

Check the referenced boatsetup.com chart.
 
You must log in or register to reply here.
Top