Exhaust leaking through steering bracket? Also, removing the long shaft... 1986 Johnson 6hp tiller

First off, thanks to everyone (and the owners of this forum) for all the help you've given me with this motor. I'm a rookie at outboard repair and this motor is giving me a pretty good run for the money.

I think I have it running well now (throttle issues, carb cleaned, etc) but I have a pesky exhaust leak that I'm having trouble finding out how to approach. If I leave the cowl on, the motor eventually starts to stifle and doesn't run well at all (takes only a couple minutes to begin). There's always a small amount of 2-cycle smoke coming up from around the motor around the bracket that mounts to the transom, and around the tiller's main bracket.

You can see in the pics where I've put arrows to the two places I've seen the exhaust coming from. This has left oily deposits in these areas, and there's oil specks all in the lower part of the cowl. Apparently this has gone on for a while.

If this repair involves removing the middle section, I may just remove the extension that makes this a long shaft, since even with a jack plate raising the motor up a good 6", the AC plate still sets a couple inches below the keel. I think raising it up some will help this boat move along a little better. Adding the jackplate, by itself, increased my speed some.

I do not know if this matters, but the gear shift knob does not shift into reverse. Seems like it is in the same place as the exhaust leak, and I was told that someone bumped it a while back (previous owner). Not sure what happened other than the shift knob got jammed in a little, if you try to put it in reverse, it hits the lower cowl and you can tell something inside is jammed up.

I wasn't going to fiddle with the reverse for now but if I have to remove any of this, or if it's related, I'll try to fix it.

Does this help?

Any suggestions?

Most likely a leaking gasket. Remove the powerhead and change the gasket.

Thanks, that's what I was suspecting but I was hoping for a simpler repair... lol.


I have never removed a powerhead. I obviously won't ask for a step by step, but are there any pitfalls to avoid in doing this, generally speaking? What I don't want to do is to get halfway through and have stuff come apart that I won't know how to put together.

This motor is essentially my "outboard training course". It's given me ample opportunities to learn how to maintain these things lol. But it always cranks and runs.

Biggest 'pitfalls' are broken bolts when removing! Get a propane torch and be prepared to use some heat. Before using the torch, it might be wise to remove fuel components like carb and pump first!

Good point haffiman, thanks. I will do that.


Would an exhaust leak cause a bit of hesitation when accelerating? My carb is rebuilt (new kit a month ago) and I've adjusted the idle jet (no high speed adjustment on this one), but no matter how I adjust the idle jet, the motor wants to hesitate when I accelerate. It bogs down momentarily and sometimes will want to stall on me. Fuel pump's screen is totally clean.

The hesitation is hard to try to adjust out. I had it on the river Friday and no matter what I did, it wanted to hesitate. Note that it didn't do this at all until I did a de-carb by spraying seafoam through the carburetor. The carb was clean but the spark plugs (when I first bought it) had a lot of burnt oil deposits on them, so I cleaned them, but it suggested that the previous owners mixed the oil too too rich.


The de-carbon really did seem to smooth out the idle, and the motor purrs like a kitten up to about half throttle.

I can't find a needle adjustment that doesn't cause hesitation really. This carburetor has a plastic top that has a hairline crack in it that I epoxied up, but I fear air may still be leaking through it. But it didn't hesitate like this until I did that seafoam decarb.

I've since removed the carburetor and double-checked everything in the carb. It's clean as a whistle inside, so far as I could see. The only possible exception perhaps is something small clogging the main jet that I can't find.

kimcrwbr1 said:

Dude you all ways fix the obvious first. Until you replace that cracked cover you cannot eliminate is as a variable. Did you call seaway for a price and availability of a new cover? I would pull the powerhead and check the shift gears first, make a list of parts up and put it back together correct then you can continue with the diagnostic if necessary.

Click to expand...

A cracked carb top isn't going to cause an exhaust leak, which is the main point of this thread. That's by far the most obvious actual problem. The motor didn't start hesitating until I did the Seafoam de-carboning, and I don't think the crack got any worse just because of the Seafoam. I do realize the sensitivity of a carburetor but I'm not convinced that the crack is exactly what's causing the problem. I need to replace it at some point in time but the motor wasn't hesitating before I SEafoamed it. Maybe something tore lose and got into the hs orifice, I dunno.

I have not yet called Seaway because I work all day (not saying to be an ass, it's just the case, I can't easily get to a phone for personal stuff).

Agreed, really.

Note that this motor had an enormous amount of neglect over the past 5-8 years, so at this point I've done a LOT to fiddle with it, and along the way I'm learning. I've never once worked on an outboard motor until this one.

I had to make a linkage from the cam follower to the throttle on the carb, out of 1/8" aluminum. I had it drilled wrong and wasn't opening the butterfly enough. Took me a while to figure that out, but now I have that fixed and it WAS running like a champ (other than the exhaust leak and a bit of a rough idle). I decarboned with Seafoam and now it's hesitating. I'll pull the carb later this week and see if the hs orifice is plugged.

Go buy a second hand motor from craigslist. Around 4-6 hundred and put that one up to tinker with in your spare time. Then you have a back-up motor or you can re-sell it when you get it straight. Other suggestion is to get your parts from e-bay ( they have plenty out there ) and start re-placing the broken, worn out pieces gradually. Been there before. It allowed me to fish all summer and on rainy days work on the motor without screwing up my fishing or making me second guess if I was gonna get stranded....

Scott, that's exactly what I intend to do, except I may trade this off for a trolling motor.

I have a source of a 7.5 (the serial says it's an 8hp but the cowl says 7.5) that's a 1983. The carb is the older metal style and less plastic crap in it. In good shape. I'm also eyeballing an 89 Merc 15hp.

Thanks!
Matt

Just an update.

The motor seems to run quite nicely if I put the baffle back on. I've been running it with the intake baffle removed because I was adjusting the carb (really, to be honest, just messing with it to learn how it works and how various settings affected it). I set the screw to what seemed to be the most useful setting and put the baffle on, and yesterday the motor ran quite nicely.

It still has a very slight hesitation when I accelerate strong ("hole shot" or anything close to it), but it's nothing like it was. I may still have something in the main jet but I can get full speed out of it. Yesterday was the fastest this motor has pushed this boat (by GPS) which was 8.3mph, after messing with the trim settings. A while back I installed a high-jacker jackplate that got the long-shaft up close to the right height, and that has also helped tremendously. Even with the jackplate, the best I was able to get sustained was an somewhat unstable 7.3-7.7 but it varied a lot (motor wouldn't run predictably).


Yesterday, after a very brief hesitation, it would run very stable. So now really I'm just looking at the exhaust leak and lack of reverse. Just requires pulling block off and fiddling with the midsection. Thanks for the help all! I've learned an ENORMOUS amount from you all, not knowing anything about boats previously.