Topic: 1989 15 Johnson plastic carb issue – Antique Outboard Motor Club,Inc

This topic has 10 replies, 7 voices, and was last updated 5 years, 10 months ago by outbdnut2.

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June 28, 2018 at 3:00 pm #10396
outbdnut2
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I have 5 of these 15 HP Johnsons from this era that have mega-hours on them and came from a failed resort. I pulled the carb on one of them and took care of some internal issues, but when I put it back on the motor, the special screw that the throttle cam roller bracket pivots on, stripped out when I tightened it into theside of the plastic carb top. The screw is fine, the plastic threaded hole is stripped. Has anyone else had this happen and come up with a fix for it? For the time being, I fixed it by putting loctite on the screw and after assembling it, I wrapped a piece of thin wire around the carb, laying it in the screwhead slot so it can’t turn or move out of the hole. I carefully found a route around the carb that did not interfere with moving parts before twisting the wire ends together. I put the wire because I don’t know if the loctite I used will bond to the plastic.

I think maybe this one had that screw removed and overtightened too many times over the years as I have not had this problem on others I’ve worked on.
Dave
June 28, 2018 at 3:31 pm #78618
Anonymous
I do not know if the area around the hole has enough meat to heilcoil repair the threads, other wise replacement of the plastic cover may be the way to repair it.
June 28, 2018 at 4:40 pm #78621
jerry-ahrens
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US Member
The original plastic top is NLA, and will supercede to a new kit assembly. Check Marine Engine for part #s. They aint cheap either. I always tell people to handle that carb with extreme care.
June 28, 2018 at 5:29 pm #78623
dan-in-tn
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This might not seem like much of a fix & might not work in this case, but worth a try. Depends on the strength needed? Take the small piece of left over tyrap (black is best) & put it in the stripped hole. It is the same material (#320107 is)
Put the screw back in & screw it in. It will make new threads & bond to the plastic. You will need to do it again if you take the screw out. Works in most cases! Worth a try & free.

Dan in TN
June 28, 2018 at 10:07 pm #78632
outbdnut2
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US Member
Thx – I’ll try the piece of tyrap or other similar plastic next time I take it apart. Marine engine has a "carb cover kit" # 0433973 but at $125.00, that’s more than I paid for the whole motor! Meanwhile, I put it on a boat and it’s holding together with my Rube-Goldberg fix. Helicoil just doesn’t sound good in this plastic.
Dave
June 28, 2018 at 11:15 pm #78634
fleetwin
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US Member - 2 Years
Yeah, such a shame about the ridiculous price for the replacement part…
Whatever method you came up with for supporting the stripped screw is fine, now just be on the look out for more affordable repair kits/tops…
June 28, 2018 at 11:19 pm #78635
fisherman6
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US Member - 2 Years
Dave, I have not looked at one of these carbs to see this part of it. I have a 15 and a 9.9 and they are both metal carbs. We have used thousands of Helicoils in plastic (UHMW, Nylon, Delrin, etc.) sheets at work. Whenever they see any kind of stress or are a part of something that gets removed semi regularly, the tapped holes get Helicoils. I’d bet a shirt Helicoil would work here unless it is barely larger than the screw.
-Ben

OldJohnnyRude on YouTube
June 29, 2018 at 12:00 am #78639
PugetSoundBoater
Participant
Dave-I just got done rebuilding one of these carbs also , same year and HP. I was Very Careful not to over tighten anything. I had looked at the cost of the parts, holy cow be gentle came to mind ..repeatedly.
I like Dan’s idea of the tywrap scrap to fill the stripped out threads. I would probably use the very tip of the end, which is thinner than the center section and will work just fine. There is not a lot of stress or tension on that screw that holds the cam roller on. Being a shouldered screw,It is a looses fit when tightened ,in order for the roller to move. I believe the later years had a stud that the roller fit on instead of a screw.
I have another one of these ’89’s,a 9.9 Johnson to rebuild the carb on…looking forward to that. 🙂
Jim PSB

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson
June 29, 2018 at 2:21 am #78646
outbdnut2
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Thanks everyone for all the suggestions. It’s running super good right now at all speeds, so I may just leave my Rube-Goldberg fix in it and see if it holds – running it a lot in the next 3 weeks before I take it as one of three 15s to Canada for a week long houseboat fishing trip. We put 8 to 10 guys on a 58 foot houseboat on Lake of the Woods 90 miles into Canada from Minnesota; and tow fishing boats in two strings behind it – we have towed as many as 7 boats. The 15s go on 14 and 16′ Aluminum open rowboats that we drag into small portage lakes, using a couple bigger boats for the main lake. The wire I wrapped around the screw and carb is stranded/braided copper – kind of like steel picture hanging wire – I’m thinking I’ll solder the twist area so vibration doesn’t make it come apart. If my fix doesn’t hold, one of the three motors I take is a spare.

Below is a photo from last year – only had 6 guys, so a slightly smaller houseboat (54 foot). Note the extra steering wheel at the rear of the houseboat up top so you can see where you are going while backing up!

FYI: Lake of the Woods, with all it’s islands channels and bays has more total shoreline that the east and west coasts of the 48 states combined!
Dave
June 29, 2018 at 2:26 pm #78666
fleetwin
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US Member - 2 Years
Boy, that sure look like a great time!
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