73 johnson 115.. piston hits spark plug.

[Faztbullet]

Re: 73 johnson 115.. piston hits spark plug.

That engine uses perma gap plugs which are flat,

 

[Willyclay]

Re: 73 johnson 115.. piston hits spark plug.

Here's a link to the spark plug specs:

http://www.boatsetup.com/SparkPlugChart.pdf

 

[ezeke]

Re: 73 johnson 115.. piston hits spark plug.

Here's a link to the spark plug specs:

http://www.boatsetup.com/SparkPlugChart.pdf

That link (chart) is out of date; this one updated to March 2009 is more recent: http://continuouswave.com/whaler/reference/BRP/SparkPlugChart2008.pdf

Boatsetup does have one updated to 2007: http://boatsetup.com/Spark Plug Chart 2007 BRP.pdf

 

[Willyclay]

Re: 73 johnson 115.. piston hits spark plug.

Thanks for that info but I don't see his 1973 Model 115 listed.

 

[crxess]

Re: 73 johnson 115.. piston hits spark plug.

That engine uses perma gap plugs which are flat,

Surface plugs tend to run cold and foul to much. That is why a newer Gap adjustable plug is listed.

 

[ezeke]

Re: 73 johnson 115.. piston hits spark plug.

Thanks for that info but I don't see his 1973 Model 115 listed.

That's because you have to get it from the parts catalog or the dealer. The listed plug for the 1973 115 is still UL77V with several special use alternatives.

The charts in the several links above are not OMC/BRP publications but are the best aftermarket listings that I have seen.

 

[ezeke]

Re: 73 johnson 115.. piston hits spark plug.

Surface plugs tend to run cold and foul to much. That is why a newer Gap adjustable plug is listed.

It (gap adjustable plug) is not listed in the newer chart and that is the point.

 

[crxess]

Re: 73 johnson 115.. piston hits spark plug.

Ezeke, I found the plug on a marine suppliers chart for that motor.

Also found this on a post for a 73 115hp:

Joe Reeves's Avatar
Joe Reeves Joe Reeves is online now
Admiral

Join Date: Feb 2002
Location: Central West Florida
Posts: 6,582
Default Re: Calls for UL77V Can I use QL77JC4?
SparkRoost..... Use the Champion QL77JC4 plugs with great ease of mind, and set the gap to .040 . It is a alternate plug recommended by OMC for that engine, to be set at that gap setting.The UL77V plugs work in many engines but unfortunately, regardless of the "77" rating, they have no real heat range and are quite prone to fouling.

In the short time I have neen here I have come to trust Joe's input.

 

[ezeke]

Re: 73 johnson 115.. piston hits spark plug.

Trust this: if the QL77JC4 hits the piston, the UL77V probably will not.

I own and run both the the 115 and 135 in the 1973-1976 series, and depending on which cylinder heads, gaskets and whether the cylinder heads have been milled or not, the QL77JC4 has always been reliable for general use.

 

[naturallysmashed]

Re: 73 johnson 115.. piston hits spark plug.

wow thank you everybody for your help, this seems like a great community. I see all these different spark plugs.. i'm not sure which to go out and get to see if it makes a difference!! if anything one that would stay a little further from the piston would be better, no?

 

[gazza2007au]

Re: 73 johnson 115.. piston hits spark plug.

listen to what faztbullet said he knows hes johnson/evinrudes!

 

[Joe Reeves]

Re: 73 johnson 115.. piston hits spark plug.

The QL77JC4, gapped at either .030 or .040 should operate perfectly in that engine with adequate clearance. Since it does not, at the present, I would agree with others to use the UL77V plugs or extra plug washers on the QL77JC4.

However, think about it...... from what I understand in your posts, it is only one cylinder that hits the QL77JC4 plug, and the same cylinder every time?

If so, I suspect that you have either piston play, one wrong piston installed, excess build up on the dome of one piston, or a shaved head or block. Unlikely that a shaved head or block would affect just one cylinder though.

 

[naturallysmashed]

Re: 73 johnson 115.. piston hits spark plug.

The QL77JC4, gapped at either .030 or .040 should operate perfectly in that engine with adequate clearance. Since it does not, at the present, I would agree with others to use the UL77V plugs or extra plug washers on the QL77JC4.

However, think about it...... from what I understand in your posts, it is only one cylinder that hits the QL77JC4 plug, and the same cylinder every time?

If so, I suspect that you have either piston play, one wrong piston installed, excess build up on the dome of one piston, or a shaved head or block. Unlikely that a shaved head or block would affect just one cylinder though.

really I'm just trying to come up with any excuse not to do any internal engine work.. i may try the ul77v and just use the boat the rest of the year and rebuild over the winter. hopefully it holds up, thank god for my towing membership. would I have to buy a ul77v for every cylinder or just the one? i don't see much build up, one of the first things i did when the engine was running was de-carb it too. it's pretty clean inside there... and a shaved block should affect both plugs on that side, or else i should have a gasket leak.

 

[troutmaster1972]

Re: 73 johnson 115.. piston hits spark plug.

Just saw this thread and reminded me of something that just happened to me and thought maybe you had the same issue Needed plugs for my 1985 4 horse Johnson Go to the local Advance Auto and since they keep the plug book behind the counter I had to have the clerk cross reference for me When I got home I decided to compare plugs to the old ones just for kicks The new ones were a good 5/8 of an inch or so longer!! Glad I didnt just put em in and fire it up Turns out the plugs were fo a 90 horse When I returned plugs explained to the same clerk that if I had of run the plugs she sold me I would have put them right through the pistons She just gave me a blank stare like it was no big deal Wonder if maybe somebody did the same to you

 

[ilovefroggin]

Re: 73 johnson 115.. piston hits spark plug.

really I'm just trying to come up with any excuse not to do any internal engine work.. i may try the ul77v and just use the boat the rest of the year and rebuild over the winter. hopefully it holds up, thank god for my towing membership. would I have to buy a ul77v for every cylinder or just the one? i don't see much build up, one of the first things i did when the engine was running was de-carb it too. it's pretty clean inside there... and a shaved block should affect both plugs on that side, or else i should have a gasket leak.

Your not getting it. You seem to be fixiated stubbornly that there must be internal damage to your motor. That is not what the experts here are saying. They are saying the plugs you used were too long.

Just go get the reccommended plugs, the UL77V or the QL77JC4, install them adn you should be good to go. Dont take off the rings, gap them to the proper spec.

Report your results after you have tried the proper plugs before you worry about tearing the powerhead off.

These guys know what they are talking about.

 

[ilovefroggin]

Re: 73 johnson 115.. piston hits spark plug.

However, think about it...... from what I understand in your posts, it is only one cylinder that hits the QL77JC4 plug, and the same cylinder every time?

He also mentioned he lost the spacer ring on one spark plug, most likely the same one that was getting hit.

 

[Big Bubba]

Re: 73 johnson 115.. piston hits spark plug.

I agree wholeheartedly with Ilovefroggin. These guys are AWESOME on this forum and they have my upmost respect when working on these outboards. If it wasn't for this forum I would have never, ever worked on my outbaord. Becuase of these guys they gave me the confidence I needed to push myself to doing my own work on my outboard. Take care, Bob

 

[emdsapmgr]

Re: 73 johnson 115.. piston hits spark plug.

Was you engine ever torn down for an overhaul? Something else to consider. OMC changed the length of the rods along with the height/location of the piston pin in 74. If someone overhauled the engine, got the wrong year and ordered and installed a single wrong rod or piston, you could have a mismatched clearance issue that you describe.

 

[mikesea]

Re: 73 johnson 115.. piston hits spark plug.

i agree with the fact that electrode or no electrode,the eng should accept either,based on what was posted with the ql77jc4 being an alternate and having put many in for guys that trolled alot,now,you have 1 cy,with the problem,and it likely a small measurement of trouble,what comes to my mind is age of motor,if that head has been dressed up many times over the yrs ,he could very well have a head that has been machined down too much,next question would be why one cyl and not the 2.well,ive seen guys do all sorts of crazy stuff,from holding the head on a belt sander,not the little hand sander a bench sander,attempting to get warp out,so,its possible,the head was sanded,milled whatever while either not flat,or a warp so bad ,with a sanding so excessive ,he now has a head over milled.I suggest,take the head off,measure it up and compare to spec.or try another head,now,if the eng block was decked and too much the same result could apply.I believe an oversized head gasket may be available,I know the 6 cyl had them to reduce cmp.but as for the 4.Maybe someone else knows.My opinion is mine only and I say its not the plug or rod or piston but head or block.

 

[mikesea]

Re: 73 johnson 115.. piston hits spark plug.

i agree with the fact that electrode or no electrode,the eng should accept either,based on what was posted with the ql77jc4 being an alternate and having put many in for guys that trolled alot,now,you have 1 cy,with the problem,and it likely a small measurement of trouble,what comes to my mind is age of motor,if that head has been dressed up many times over the yrs ,he could very well have a head that has been machined down too much,next question would be why one cyl and not the 2.well,ive seen guys do all sorts of crazy stuff,from holding the head on a belt sander,not the little hand sander a bench sander,attempting to get warp out,so,its possible,the head was sanded,milled whatever while either not flat,or a warp so bad ,with a sanding so excessive ,he now has a head over milled.I suggest,take the head off,measure it up and compare to spec.or try another head,now,if the eng block was decked and too much the same result could apply.I believe an oversized head gasket may be available,I know the 6 cyl had them to reduce cmp.but as for the 4.Maybe someone else knows.My opinion is mine only and I say its not the plug or rod or piston but head or block.If there was that much slop,the eng would be short lived