1971, 20hp with strange spark plugs.

[Bearcamp]

I just bought a 1971, 20 hp Johnson and got a nice price. Tried to get it running and had no fuel. So I removed the carb, needle abd seat were stuck. A little cleaner and started right up. Went to shut it down and the kill switch was unplugged so I had to choke it out. Wrong move, was that baby hard to start after that and fouled 1 sparkplug. I removed the plugs and never saw ones like these. Just flat with no electrode. Can I replace them with regular plugs and what number? Also can I install electric start on this motor? What all will I need to do so?

 

[Joe Reeves]

Re: 1971, 20hp with strange spark plugs.

That's a surface gap spark plug which has no business being in a 1971 18hp, 20hp, or 25hp engine. The proper spark plug is a Champion J4C, and the alternative s/plug is a Champion J6C. The gap would be .030. The J6C may give you a better idle.<br /><br />Perhaps the engine is not a 1971? What is the model number of the engine?

 

[Paul Moir]

Re: 1971, 20hp with strange spark plugs.

Those are the wrong spark plugs.<br />You want Champion J4C sparkplugs gapped at .030". Those plugs you've got are called 'Surface Gap' plugs and are used in some of the larger outboards.<br /><br />For electric start, you'll need a starter, solenoid, wire, starter bracket, and possibly a flywheel if your one doesn't have teeth in it. Best bet is to go find the local outboard junkyard and scavange. I'm sure Twin City could set you up. I expect all that from any 60's 18-25hp (22.0CID block engines) would work fine. Also, be aware you may also be looking for a carb with an electric choke if you're thinking of going remote.<br /><br />Hope this answers your Qs.<br /><br />EDIT: Joe posted while I was typing. Sorry about the collision, Joe!

 

[MFG197]

Re: 1971, 20hp with strange spark plugs.

Ballpark figureb What did you pay for the motor? (looking at a '75 25hp evinrude Long Manual)

 

[Bearcamp]

Re: 1971, 20hp with strange spark plugs.

Ok, the plug that is in now is a Champion J76V. I'll get the right ones. Model number is 20RL71S and serial number is E3430841. I paid 395 and it's a very clean motor. You pull that cord to start and you really gotta tug. About like kick starting an old 1960 Harley.<br />And Paul, I'll check with Twin City.

 

[68wetboat]

Re: 1971, 20hp with strange spark plugs.

What about disassembling the pull start? The spring isn't the easiest to get back on...but might want to invest a little time/energy into finding out why it's so hard to start (bad rope, bad spring (new spring is probly less than 10$ from iboats part finder))<br /><br />Or if you don't want to mess w/ spring, I've seen new pull start top units for under 20$ on ebay.<br /><br />good luck

 

[Bearcamp]

Re: 1971, 20hp with strange spark plugs.

Well I did take the plugs out and then pull it. I believe the compression is that good. Cause you can feel it when pulling. Pop, pop, pop. I didn't look to see if it has a compression release. Just purchased a manual for it, so I'll be able to read up on it.

 

[MFG197]

Re: 1971, 20hp with strange spark plugs.

Thanks, this guy wants 500 pretty steep, NADA is like 80 bucks, but anything is worth what someone will pay. Is it that hard to start? It's acutally my dad looking and he is in his 60s

 

[Bearcamp]

Re: 1971, 20hp with strange spark plugs.

Well we'll see after I install the new plugs. Maybe too I just had it flooded out with the wrong plugs. I'll let you know. Hey Joe....you say the with the J6C I might get a better idle. Why is that? Are they a hotter plug? And are they fine to run in this 20 hp?

 

[DJ]

Re: 1971, 20hp with strange spark plugs.

The J6C is slightly hotter. <br /><br />No one on this board knows more about OMC engines than Joe. Heed his advice.

 

[Bearcamp]

Re: 1971, 20hp with strange spark plugs.

You say slightly hotter? Won't harm anything will it? I mean like over time.

 

[DJ]

Re: 1971, 20hp with strange spark plugs.

If Joe says they're OK, that's Gospel to me.