Quick question on this OB

[Bradster941]

Quick question on this OB<br /><br />Model Number :E90TLCNB<br /> <br />Serial Number : J013298d2<br /><br />Is the correct plug a QL77JC4 gap at .030 <br />And is it a 1977<br /><br />Many thanks…

 

[MCM]

Re: Quick question on this OB

Spark plugs recommended are QL77J4 or UL77V. Motor is a 1982.

 

[BoatBuoy]

Re: Quick question on this OB

Model number indicates it's a 1982. If that's the case, the plug you referenced is correct, also the gap

 

[TimMattson]

Re: Quick question on this OB

Our dealership has always used the NGK plugs in the OMCs with goodluck,Napa has them cheaper than our boatstore....<br /> Run Engine tuner or Carbon Guard thru before swapping plugs and after a good hard run to blow out the black crud.<br /> No premuim either!87-89 w/ Tcw 3-4 oil.....<br /> Tim M

 

[Bradster941]

Re: Quick question on this OB

Thanks Mike, Tim, and Buoy.<br /><br />I should have looked a little closer at the serial #.<br /><br />Personally, I've had problems with the NGK's in past years Tim, so stick with Champions.<br />Good tip on Carbon gaurd. I Sea foam it and then winterize it every Spring before putting it to sleep. Also about the octane, wish more people new the cheap stuff is better for the engine. <br /><br />Hmm, is it QL77J4 or QL77JC4 Mike and Bouy?

 

[ezeke]

Re: Quick question on this OB

It is ***JC4: Spark Plug Chart

 

[rodbolt]

Re: Quick question on this OB

be wary using NGK plugs in later model motors with SLOW and quick start, the NGK plugs use a carbon resistor as a noise suppressor and the champion use an inductor, the EMI and ring effects can play with certain sensitive circuits causing everything from driveability issues to false alarms.<br /> I have found over the years if I just put back in it what the engineers and tech bullitens tell me the dang things actually just work.<br /> the carbon resistor is a main reason most japanese motors with high output ign systems use a resitive plug cap.<br /> if you dont beive in the spark plug resistance values measure the next set with your ohm meter from the center electrode to the cap electrode and compare them.

 

[Bradster941]

Re: Quick question on this OB

Thanks Guys, was pretty sure it was that.<br /><br />Rodbolt, good point. I have read in the past about how plugs were made and was amazed at the engineering that goes into them.