Is anyone into Johnson/Evinrude Rotary Powered Snowmobiles?

I have a Johnson Rotary 35 I've had for about 7 years. I haven't ridden it in a few years, but I want to fix it up over the summer and I need a spark plug.

Now, I've gone through every channel possible to find a new spark plug (NOS). Champion was the only one to produce a plug for the 35hp model and they discontinued it in the late 80's and NOBODY makes a replacement. I've gone through Ebay, craigslist, etc, and have gotten nowhere.

The model (if I remember correctly) is Champion U77V.

Thanks to anyone that can help.

*Edit- I found a picture of my Johnson

your johnson is awesome rob. i didnt know you ever got it running. what's so special about it that you couldnt just take it down to a small engine shop or autozone and match it to thread/reach/heat range?

This chart lists a UL77V, for a JX400 Johnson...is that it?

http://www.championsparkplugs.com/results_appOther.asp?otherMotiveID=6620&mfid=2 They also have a bunch of listings for OMC engines, I don't recall if OMC ever built Wankel outboards or not.

Would it be the same plug used in an Arctic Cat Wankel sled? They do have a couple listing for them as well.

I just got home to look it up and it's a UP77V. That's the one that's discontinued. It's a 12mm Thread size, with a half inch reach.

The UL77V is used on the larger 45hp Johnson rotary.

WOW ! we used to play "Spot the obscure Snowmobile" while riding in the Adirondaks and yours would have been a winner for sure !

Good Luck !

The Suzuki rotary bike owners have the same issues with spark plugs being discontinued and hard to come by.

Any way you could adapt your snowmobile to accept spark plugs for Mazda rotaries?

In reply to RexSeven:

It's a surface gap plug, and I'm not boring out the engine to fit a larger plug. I do not have a service manual to this sled, I don't want to have to pull the engine apart.

Try some vintage sled forums? I found nla parts at a junkyard this way.

I've tried the forums, found a guy selling a new plug in a box, hope he responds, still has it, and doesn't want an arm and a leg for it.

Do any of these guys modify or ad something to a currently used plug ? Snowmobiles (especially older ones) require plugs fairly frequently

The Surface Gap plug can last a long time, if fouled out, it can be taken out, cleaned with a wire brush and it will run like a charm.

I believe this is what they call an "Advantage"

SyntheticBlinkerFluid wrote: The Surface Gap plug can last a long time, if fouled out, it can be taken out, cleaned with a wire brush and it will run like a charm. I believe this is what they call an "Advantage"

Is a surface gap plug a funky ring with the center sending arc in any of the 360 degree around it ? I can't remember some of the older funky plugs...

In reply to Chebbie_SB:

Yes

Argh, I've spent most of my sleepless night looking for anything and once again, no avail. I'm still waiting on this guy to respond back to me.

I have also found that there are many other people out there looking for the same plug, I wish that I could round up these people and get petition going for champion to make a limited run of these spark plugs. I know it wouldn't be feasable, but damn, this sucks.

That Plug, UP77V is the only plug ever made for the Evinrude Rotary Snowmobile engine. It fits both the 35 and the 45 hp version. The Apex seal on the rotor actually wipes the end of the plug, so if it isn`t perfect, disaster strikes!! Many people drill and tap the rotor housing to accept a 14mm surface gap plug, but to do that correctly, you will need to dissassemble the engine. When I first got my Rotary 45, I modified a D8EA NGK (correct thread, much longer reach) spark plug to fit. I basically cut it down to the correct length and polished the end. Believe it or not, this worked and ran quite well for many years. THere are companies selling modified plugs for these engines. THere are still some NOS plugs availiable, I got a few from a guy in Minnesota that has lots of parts for these old OMC sleds. If you want to e-mail me I will give you his number. Guy

Yeah, PM me, I want a new plug, but do you have info as well on the modified plugs people sell?

This is why I love it here:

ironhead wrote: That Plug, UP77V is the only plug ever made for the Evinrude Rotary Snowmobile engine. It fits both the 35 and the 45 hp version. The Apex seal on the rotor actually wipes the end of the plug, so if it isn`t perfect, disaster strikes!! Many people drill and tap the rotor housing to accept a 14mm surface gap plug, but to do that correctly, you will need to dissassemble the engine. When I first got my Rotary 45, I modified a D8EA NGK (correct thread, much longer reach) spark plug to fit. I basically cut it down to the correct length and polished the end. Believe it or not, this worked and ran quite well for many years. THere are companies selling modified plugs for these engines. THere are still some NOS plugs availiable, I got a few from a guy in Minnesota that has lots of parts for these old OMC sleds. If you want to e-mail me I will give you his number. Guy

okay Im reviving this thread:

just saw this:

http://detroit.craigslist.org/mcb/rvs/3576301906.html

I crave rotary sled

SyntheticBlinkerFluid, there is a guy in Kankakee--L&G Marine--Ask for David. He has the same engine that he is trying to turn into a cart, and he had the same problem you have. Might want to get in touch with him, he might have found a solution by now.

Haha zombie thread.

I'll have to look into that mtn. Thanks

Could I swap a 13B in there?

In reply to DaveEstey:

Too big.

DaveEstey wrote: Could I swap a 13B in there?

Save that for a newer sled, maybe an RXL or something. 45hp in one of those would certainly pick up a ski.

SyntheticBlinkerFluid wrote: In reply to DaveEstey: Too big.

So yes.

Again, just reviveing this thread. I was reading through it and remembered that I have a 1973 evinrude and Johnson snowmobile service manual for the 35 hp wankle motors. if anybody wants pics to help them out I am willing to help!