will this hurt a motor?

[levi_tsk]

i have a j140tlcim and i went to worst marine a few weeks ago to get spark plugs -the guy there sold me the wrong plugs (L77J4's)
yesterday i was thumbing through my omc service manual (its oem) and i noticed that the proper plugs according to my manual are UL77V this has me freaked out and i wanted to know if running these plugs will hurt anything ?
i plan on running the proper ones but i ran the motor with the other plugs for an hour or so
thanks for the help

 

[1946Zephyr]

Re: will this hurt a motor?

Nahh, won't hurt anything, but it may affect performance.

 

[Joe Reeves]

Re: will this hurt a motor?

J140TLCIM = 1981 140hp Johnson.

The Champion UL77V Spark plugs are one of two plugs recommended for that engine. The UL77V is a surface gap plug which really has no heat range regadless of the "77" rating, and therefore is subject to fouling more so than the alternative plug which is (as sold at that marina) the Champion L77JC4 or QL77JC4 (Q = suppressor plug).

Frankly I prefer the QL77JC4 plug, gapped at the original recommended .040 setting.... some prefer the modified .030 gap setting. One setting or the other may give you improved performance at top end (or idle).... try both gap settings and decide.

Hopefully this eases your suspicions on the spark plug issue.

 

[levi_tsk]

Re: will this hurt a motor?

SWEET!!! thank you joe i really appreciate the info

 

[jay_merrill]

Re: will this hurt a motor?

On the advice of my local OMC/BRP dealer, I run the "J plugs" in my '72 Johnson 65hp too. Overall, the motor seems to run better.



???

 

[F_R]

Re: will this hurt a motor?

Many of these grey hairs I have are from trying to make those blankety-blank surface gap plugs run right. The (Q)L77JC4 are a life saver. I agree with Joe.

 

[Dhadley]

Re: will this hurt a motor?

Yep, me too. With todays fuel I'd much rather use the (Q)L77JC4 in that motor. Remember - when you look in a 1980s service manual the recommended spark plug was with that fuel in mind. That fuel makeup is long gone....

 

[levi_tsk]

Re: will this hurt a motor?

alright thanks guys!!!
ill run the ql77jc4 plugs then
would someone mind explaining a suppressor plug to me ?
what does it do ?
what was the intent with the surface gap plugs?

 

[Joe Reeves]

Re: will this hurt a motor?

The "Q" indicates a suppressor plug, the purpose of which is to quiet or help quiet ignition noise etc in various electronic equipment that one may have on board (radios, depth sounders [fish finders], etc).