1977 Evinrude 140hp Plugs?

[LV2FISH4CATS]

I bought a Lund Tyee 1950 with a Evinrude 140 V4. It was not running right so i took the plugs out and found that they are different than the recommended plugs? They are a L77JC4 the book calls for UL-77V? my concern is the plugs I pulled out? One of them had the ground leg bent over flat like the piston slapped it? I looked into the plug hole but could not see any damage? I just ordered a compression tester and will check bleed down on that cylinder?? Is there anything else I should check?

 

[Joe Reeves]

Re: 1977 Evinrude 140hp Plugs?

Use Champion QL77JC4 plugs, gapped at .040 . Those UL77V plugs have no heat range and tend to foul easily.

You'll need to remove the cylinder head to insect the piston surfaces, cylinder wall, etc.

(Piston Play Check)
(J. Reeves)

This procedure will tell you if there is any wear or play in the Wrist Pin, Wrist Pin Bearing, or Connecting Rod to Crankshaft area.

Remove the spark plugs. Insert a screwdriver, dowel, punch, or some object of your choice through the s/plug hole and into the cylinder/piston area. Hold the tool lightly against the top of the piston. Turn the flywheel by hand, bringing the piston up to top dead center, then continue turning the flywheel to pull the piston down about a inch..... all the while holding the tool lightly against the piston top.

Now, at the point whereas the piston has been dropped down about a inch, grab the flywheel and hold it firmly. Now, push that tool solidly and firmly against the piston top.

If the piston moves without moving the flywheel, there is a problem (wear, play, clearance, etc) somewhere with the items mention in the first sentence. Be sure to check all of the pistons/cylinders.

 

[Vic.S]

Re: 1977 Evinrude 140hp Plugs?

I expect Joe is right but all the lists give UL77V for that engine. They are surface gapped plugs and more suited to sustained high speed use. The alternatives for slowspeed use at one time listed were L77J4, but you would now substitute L77JC4.

QL77JC4 are the equivalent with low resistance (inductive) supression if a suppressed plug is required. I think you'll find they are rather more expensive than the L77JC4. but the cost of a set of plugs is not that much!

 

[LV2FISH4CATS]

Re: 1977 Evinrude 140hp Plugs?

Thanks guys, Any info is helpful. I have looked up the NGK plugs?? are they any good? Not too worried about the cost difference.. 2 to 3 dollars a plug?? just wondering about them? Looking to replace the Tach on this old boat also?? I have the Evin-Johnson 3" Universal Tach NIB but what are the 1 2 3 4 5 6 position switch on the back for?? Do I need to change that setting??

 

[Vic.S]

Re: 1977 Evinrude 140hp Plugs?

Champion plugs always recommended for Johnsons and Evinrudes

I make the NGK equivalents
UL77V = BUHXW-1
QL77JC4 = BZ7HS-10
L77JC4 = B7HS-10
If you really must go down that route.

I think you'll find that the switch positions on the tach are the number of cylinders.

 

[Joe Reeves]

Re: 1977 Evinrude 140hp Plugs?

The tachometer operates off of the six (6) pulse charging system. Set that tachometer dial to number six (6) regardless of the cylinder count.

 

[LV2FISH4CATS]

Re: 1977 Evinrude 140hp Plugs?

Thanks Joe,

I hope one day I will be able to help others with good info like you guys offer.