1982 Johnson TLCNB115

onesubdrvr · Nov 25, 2010

Good morning, and happy thanksgiving!

I am having a problem with my Johnson, and think I've got it narrowed down, but want to make sure

As the title says, it's a 1982 115 (TLCNB115), on a 1992 SeaPro 180CC (center console V hull fishing boat)

Problem: A couple of weeks ago, I was on the water, engine was running fine, on the way back to the boat ramp, engine RPM died down to 2500 (or so). I had been running in the flats that day, and thought I might have sucked up something in the water intake, and attributed it to the SLOW system.

I rebuilt the water pump completely, took it out on the water last weekend, and the same problem, won't go over 2500rpm, regardless of weight setup / distribution, trim / etc. (trying to vary load).

So, I'm thinking it's either a powerpack, or the SLOW system, now I thought I read here that the SLOW system wasn't in use in 82, but I have two temp switches on the cylinder heads(?)

Of course, on the muffs, there is no problem what-so-ever, engine fires right up, and runs smooth. On the water, fires right up, runs smooth, just can't get over 2500.

Any suggestions would be greatly appreciated.

Thanks
Wayne

ob · Nov 25, 2010

Re: 1982 Johnson TLCNB115

I'd suggest performing a spark test at cranking speed and insure you are getting fire to all four.

onesubdrvr · Nov 25, 2010

Re: 1982 Johnson TLCNB115

Will give that a shot shortly, seems like all would be good, because it runs great without a load on it,... but will give it a go.

Wayne

ob · Nov 25, 2010

Re: 1982 Johnson TLCNB115

If the spark test checks out,the next thing of course would be fuel delivery.With boat in water and attempting to get on plane you can push in intermittedly on the fuel primer key button and see if she picks up. If so ,you likely have fouled carburetors.This is assuming that the fuel mix you were running is fresh and the tank is venting properly.

onesubdrvr · Nov 25, 2010

Re: 1982 Johnson TLCNB115

I haven't done the primer yet, but I rebuilt the carbs when I got the boat a couple of months ago, as well as putting in good fuel / oil, rebuilt fuel pump, bypass solenoid, fuel filter. Also know the tank is vented, and fuel bulb remains solid when pumped - though it does slowly leak back, and a new primer bulb is on the list. Hoses all look good with no deterioration internal or external.

Thanks, again, will try to check the spark test a little later after turkey

Wayne

ob said:
If the spark test checks out,the next thing of course would be fuel delivery.With boat in water and attempting to get on plane you can push in intermittedly on the fuel primer key button and see if she picks up. If so ,you likely have fouled carburetors.This is assuming that the fuel mix you were running is fresh and the tank is venting properly.

ob · Nov 25, 2010

Re: 1982 Johnson TLCNB115

Sounds like you did your homework on the fuel system. Make certain that each plug lead will jump a 3/8"- 1/2" gap with a good snap of blue spark.Good luck and Happy Thnaksgiving to you and yours.

onesubdrvr · Nov 26, 2010

Re: 1982 Johnson TLCNB115

Well, seems as if that's the problem;

Spark test on Stbd cylinders was good, Port cylinders not so much - I take it that those results would indicate a bad power pack on the Port banks(?).

That being said, I will replace the port side power pack, and report back with whether or not that resolved my problem.

Thanks
Wayne

mamm7215 · Nov 26, 2010

Re: 1982 Johnson TLCNB115

power pack or coils, but if it's both cylinders, then likely power pack...

onesubdrvr · Nov 26, 2010

Re: 1982 Johnson TLCNB115

Yeah, both cylinders,.... I could get some spark if I took the gap down to less than 1/4" (again, both cylinders), but nothing further apart than that. Also, found some wires that were corroded and may have gotten hot at the plug on the powerpack, again, seeming to indicate to me the power pack is bad.

But heck, the powerpack is 80$, the coils are like $10 each, I'll likely just replace everything.

Thanks
Wayne

emdsapmgr · Nov 26, 2010

Re: 1982 Johnson TLCNB115

That engine should have a matched pair of power packs. A simple test of the packs: Just swap them and see if the problem moves to the other head.

onesubdrvr · Nov 26, 2010

Re: 1982 Johnson TLCNB115

That's a good idea; I'll verify that the pack is bad tomorrow, and replace it the following weekend (heading to the Bahamas on Monday).

onesubdrvr · Dec 11, 2010

Re: 1982 Johnson TLCNB115

After having been out of town on work, I was finally able to swap the powerpack from the starboard to the port for testing, and it made no difference; there is still no spark on the port side unless the gap in the spark tested is < 1/4".

Thanks for the help, one step at a time and I'll get this

,.. so what's next?

Wayne

iwombat · Dec 11, 2010

Re: 1982 Johnson TLCNB115

Swap the coils to the other side and post results.

onesubdrvr · Dec 11, 2010

Re: 1982 Johnson TLCNB115

Swapped coils, same results,....

Thanks
Wayne

iwombat · Dec 11, 2010

Re: 1982 Johnson TLCNB115

If you've swapped everything around and the problem is still not moving, that points to your timer base.

Can you swap the leads from your timer base to the power packs? If so, see if that moves the problem to the other side.

onesubdrvr · Dec 11, 2010

Re: 1982 Johnson TLCNB115

That's what I was thinking too,... not sure if the leads will reach, but I'll give it the old college try and see if I can't get it to work.

Thanks, and will of course keep updated.

Thanks!
Wayne

iwombat said:
If you've swapped everything around and the problem is still not moving, that points to your timer base.

Can you swap the leads from your timer base to the power packs? If so, see if that moves the problem to the other side.

onesubdrvr · Dec 31, 2010

Re: 1982 Johnson TLCNB115

Well, I did replace the timing base, and verified that the spark came back,

Did the timing adjustments

Now, I just need to get it on the water and verify the problem is actually gone; I'll report back (I think I'm taking the boat out Sunday), and post what is hopefully a final post on this topic!

Thanks for the help!
Wayne

onesubdrvr · Feb 5, 2011

Re: 1982 Johnson TLCNB115

OK, got the boat on the water this past weekend, and getting out of the first no-wake zone, came right up on plane, and ran good, however, after going into the next no-wake zone, and trying to get back on plane, the problem seemed to come back,.... until I cut the motor off, removed the trim stop pin, and pulled the motor "in" even more. Once I did that, it was fine, unless I tried to trim it out some, when it would happen again, I'd simply shut it off, trim it back in, start it up and it was fine. By the end of the day, seemed to be better, but it could have been that I just left the motor trimmed in all the way after I saw the corolation. Any ideas or guesses?

Thanks
Wayne

emdsapmgr · Feb 6, 2011

Re: 1982 Johnson TLCNB115

The trim angle of the engine normally should have no affect on engine performance. In your case, it seems that it does. The trim angle may affect the fuel level inside the carb bowls. Perhaps the floats are out of adjustment inside the carbs. Any chance you have a weak fuel pump? When you have your running issues, have a friend constantly prime the fuel hose bulb. This will force extra fuel into the carbs and may change (or correct) the way the engine runs.

onesubdrvr · Feb 6, 2011

Re: 1982 Johnson TLCNB115

I will definitely check it out, I rebuilt the carbs in August, per the real manual, and when I rebuilt them, they looked like new before I started, and got very little (if any) dirt out of them. Floats were adjusted per the manual, but I agree with you, it does seem to be some type of fuel issue. I was also thinking that I should replace the fuel hose; it's not breaking down or anything, but replacing the primer bulb, and the connection on the end that "plugs" into the engine, and even perhaps the plug on the engine. I'm wondering if there isn't something causing a bottle neck there, and starving the engine when I really need the fuel, but the trimming in may "jiggle or pull" the hose and get something lined up just right to allow flow, though the carb floats seem like a better possibility.

Thanks, and although it won't happen this weekend, I'll let y'all know what I find.
Wayne

1982 Johnson TLCNB115

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