conundrum

[professor229b]

1976 9.9 Evnirude running rough and hard starting.... took it to a local mechanic.... wrong spark plugs installed (guy I bought it from). Two used spark plugs installed to confirm, no charge, nice guy.... motor runs OK but want new plugs installed... used plugs were B7HS10 NGK.... went to the local Fleet Farm and no such plug... there is a B8HS10 NGK..... but instead, went to the cross reference to find a Champion plug that would get me by, even though, in past forums, Champion plugs have been discouraged.... The cross reference led me to a marine L82 plug... I bought two... got home, got on the Evinrude sites to see what the gap should be, and saw that the Champion plug should be an UL81C...... hmmmmm not an L82? So I went online to the Champion site and did the cross reference again instead of the Fleet Farm book... B7HS10 NGK on the Champion site says L82 also.... wrote to Champion and asked for my motor, which is correct? L82 or UL81C....... waiting for a reply.... Was going to write to Evinrude but there was a disclaimer on their site that if you ask a questions about an older motor, they won't even bother to reply and to take your question and motor to a local Evinrude dealer...... which is not that easy for me..... So.... I am waiting for the answer from Champion and bet I don't get one.... anybody out there want to tell me if the L82 marine plugs are acceptable?

 

[flyingscott]

http://shop.evinrude.com/products/553609/2-Stroke here is a guide to Evinrude spark plugs. The correct plug is a UL81C gapped at .030 used for 3 yrs in that motor 74-76. The L82 is for the 1993 and up motor which is different than yours. With the motor you have it would be a good idea to go through the points. You need to be careful about NGK cross referenced plugs because they can cover a wide range of plugs. Generally they do not directly cross reference.

 

[kbait]

NGK B7HS will foul less than ul81c's.

 

[bwkre]

My 76, 9.9 service manual (10624) lists Champion L7J. I've always used NGK B7HS. Works good for mine.

 

[professor229b]

And there you have it..... the mechanic that gave me the initial diagnosis told me that NGK did make the best plug.... and that if you used the stock Champion plug which was recommended that it would foul out rather rapidly. I am pretty sure the plugs that were installed were designed for a solid state ignition (pointless) and therefore misfired or didn't fire at all..... What concerns me the most, is that the NGK plugs were not at Fleet Farm, but the cross reference was definitely L82.... and I wonder why that would be? Also, I pulled the plugs to look at them after running the motor twice with the used plugs... the ring perimeter around the bottom was already building up with a greasy oil except for a small part that was clean... that was the same on the other plug as well.... Perhaps I was running the motor to rich? Anyway... thanks for all the replies and if you read all of them, I think you can see the "jury is still out" on what is best.... I will keep looking.... Thanks...

 

[OptsyEagle]

B7HS are the only ones that motor will work with. B6HS if you can't find the B7HS. Do not use B8HS unless you like rowing. They are too cold and will foul quickly. That series of motor is very finiki on what plugs that will work with it.

 

[professor229b]

I agree..... and I debated ordering them from Ebay.... and had to research the difference between the B7HS and the B7HS-10 plugs.... and found the answer to that on an Australian website forum.... I then started in on the local auto parts stores and found Oreilly's would sell these plugs for $2.19 each which is better than I found them on Ebay.... so I will visit the store today and buy four of them...... two to install now, and two for the tackle box.... Thanks again for everyone's help... it is greatly appreciated....