[River Trapper]

Any sugjestions on plugs would be appreciated as well as where I could find a manual for this motor haven't been able to find anything local. Thanks!

[bubbakat]

QL77JC4 OR L78V OR QL82C Gap at 30Champion plugs

[rickdb1boat]

I would use Champion QL77JC4, gapped at .030. Factory Manual(Well worth it) can be ordered at the link below: web page

[River Trapper]

Bubbakat, I was pretty sure it was 30 but wanted to double check. Here's what I found for champion plugs L77JC4 is this the same as the QL77JC4 reason I ask is the motor wants to backfire now after putting in these plugs with the correct gap but if I put the old plugs back in no backfire or is there something else going on here? Thanks for the fast reply to my post much appreciated.

[walleyehed]

.030 will work fine unless you do alot of trolling or idling around. .035-.040 is better suited in the case of lower rpm use.

[bubbakat]

walleyed is right on for this and you can find these plugs at wal-mart for around 1.89 each made by champion

[rickdb1boat]

QL77JC4 is the same plug, except it is a resistor plug(Q). Same heat range. Gap at .040 as suggested and it should solve you problem. Your old plugs probably had a wider gap. If you still have them, check and see what they were gapped at. My 70 HP rude runs better at .040.

[G DANE]

Hi River TrapperIf it backfires, you probably have too lean iddle mixture ( try to turn iddle mixture screw 1/8 turn out ) or your sync´n linck it not properly adjusted. Check to see if the trottle opens before the ignition cam roller reaches center of the two small timing marks on stator plate, above carb.It will always backfire easyer on muffs, cause of no backpressure. When back in water do the procedure of adjusting iddle mixture, with boat mooving freely in forward gear. Remember to warm motor up first.