89 15hp johnson hard starting

[EagleNuke]

OK, my J15elcec is being a bear to start. I just rebuilt carb and fuel pump. Spark plugs look good and ignition parts all look good. Engine runs well once started, but is killer to get it to start.

I have been able to get it going by using a shot of carb cleaner, then it runs ok on gas, just doesn't like to start cold with gas. It will also restart ok on gas once warmed up.

I'm going to replace plugs once I figure out which ones to use, but other than that, anyone have any ideas?

 

[boobie]

Re: 89 15hp johnson hard starting

Is the choke working properly on it ??

 

[OptsyEagle]

Re: 89 15hp johnson hard starting

QL77J4C are the plugs.

Did you set the slow speed adjust properly and did you link and sync the carb to the timing advance plate? The latter is the one I would be looking at closer. There should be a mark on the throttle cam that hits the roller on your carburetor as you turn the throttle grip. When that roller just touches the cam the mark on the cam should be in the middle of that roller. If the roller is past the mark, you might never get that motor started.

The other thing to try is to forget the markings on the throttle grip and just advance the throttle until it stops at the neutral stop. Use that point for starting and see if it works better. Also, as boobie indicated, make sure the choke is closing as it should. If you remove the top of the air silencer you should be able to get a good look at it. Also, in very warm whether you may not even need a choke and the choke itself will prevent it from starting so, if you haven't done so. Give it a pull or three with the choke on, a pull or two with it off and a pull or two with it engaged half way. If it still doesn't start, it's not the choke.

 

[EagleNuke]

Re: 89 15hp johnson hard starting

Hey, Thanks for the quick responses. I'm sure the choke is ok. I have watched it several times to see that it is working right.

I haven't checked the alignment with the throttle plate. I will make that my next check.

I think the slow speed screw is OK, I opened it 1.5 turns when I reassembled everything. Not sure if there is more I should do there.

One thing that caught my eye when doing the carb kit was that the top plastic piece, that the slow speed screw goes into,appears to have a small crack in it. I can't tell if it goes all the way through enough to cause an air leak...or possibly cause some leakage between internal passages.

Also there are a few plates with internal passages, and its possible that I could have got something out of order with them. I think I got it right, but if anyone has any guidance on the particular carb, I would love the input.

 

[tomhath]

Re: 89 15hp johnson hard starting

Also make sure the priming bulb is pumping fuel to the carb.

 

[the machinist]

Re: 89 15hp johnson hard starting

If that crack goes into the threads, that would explain your hard starting (sucking air). You may try to rough up the top of theat crack area & cover it with JB Weld.

Those older plastic tops are obsolete & replacement kits are $99.75. However I am having carb problems on my 92, which is the last of that series of carbs, I bought a later top for $13 plus a new gasket for $5 & am in the process of getting a new longer needle for $27. So this is an experiment. When I get the new needle in & if it works, this may be a more economical cure for those older carbs.

 

[EagleNuke]

Re: 89 15hp johnson hard starting

Well I checked the throttle plate thing. The roller is hitting the cam just past (towards high speed side) even when the throttle handle is all the way at low speed. I don't see any way to turn the cam to even get the line/mark to the roller.

I also noticed that the top gasket on the carb has ports cut in it that don't match the picture in the parts diagram for the engine. Is this just because they didn't use an exact drawing, or do I have the wrong gasket? It is the same as what I took out. The kit came with 3 gaskets and none match the one I took out.

Anybody have a picture of the correct gasket?

 

[EagleNuke]

Re: 89 15hp johnson hard starting

Correction to my last: none of the gaskets match the diagram....the one I used does match the one that I took out. I'm just hoping that someone didn't previously install the wrong one.

 

[EagleNuke]

Re: 89 15hp johnson hard starting

I just read "Leroy's Ramblings" for the 15hp carb issues and found this:

"When reassembling the idle jet needle screw, and you forgot how many turns it was set at, a good starting spot would be to screw it in until it lightly bottoms out, then back it out about 1 1/2 turns for the pre 87 carburetors. It has been found that for the post 87s, that have the plastic top, the presetting is about 4 turns out, probably because of the finer threads on the needle as compared to the earlier needles."

I have mine at 1.5 turns, so maybe this is the problem. I will try it at 4 and see what happens.

 

[OptsyEagle]

Re: 89 15hp johnson hard starting

Well I checked the throttle plate thing. The roller is hitting the cam just past (towards high speed side) even when the throttle handle is all the way at low speed. I don't see any way to turn the cam to even get the line/mark to the roller.

Not sure I understand correctly, but the bottom line is, if when you turn the throttle grip, if that roller hits the throttle cam (I assume what you call throttle plate thing) left of that mark when looking directly at it from the front, then your motor will be more and more difficult to start, if it starts at all. The reason is because that roller and cam control the amount of gas the motor gets and with it positioned to the left of where it should be, the motor is not getting enough gas to start. You can pull the rope until the cows come home and it will not change things.

Now if you are saying that the roller is hitting the cam to the left of the mark when the throttle grip is turned completely off (counter-clockwise) then your alignment is way off, however, I am not sure what you meant by that comment. Make sure your choke is pushed in (not being used) when you are doing all these alignments. On some carbs the choke makes a small adjustment to the throttle roller, which you don't want when setting up this synchronization.

I believe on your motor there is a screw behind the roller that can adjust the roller forward. You want the mark (an elevated straight line to the right of that cam) to be in the center of the roller "just" as the roller touches the cam. If it is not there, use that screw to try to move it so it does do what I have said.

As for the gasket on your carb, I cannot advise. Perhaps others can answer that question.

 

[EagleNuke]

Re: 89 15hp johnson hard starting

You've got it right OptsyEagle. Even when the throttle handle is turned all the way in the slow direction, the mark is to the right (port) of the roller.
Seems that I need to adjust the timing plate position a little bit clockwise.

 

[OptsyEagle]

Re: 89 15hp johnson hard starting

Well it sounds like that throttle cam is in the wrong position. Unfortuneately I am not familiar enough with your model to advise on how to go about moving it. Is there anyway that you can see where that throttle cam can be physically moved to the starboard side of the timing plate?

Maybe someone who has the same model can make a suggestion on this. It sure sounds like you are going to have some troubles the way it is.

 

[EagleNuke]

Re: 89 15hp johnson hard starting

I found some good advice on Leroy's Ramblings on how to adjust it. Hopefully I can figure it all out.

 

[EagleNuke]

Re: 89 15hp johnson hard starting

OK, let me just say that "Leroy's ramblings" is a goldmine of info for someone with this motor. I happened to notice a yellowed piece of busted hardened rubber in the bottom of the housing. I wondered what it cound be...looked like some kind of sleeve.

So, I notice on LR a picture of my cam roller with a sleeve on it, and it mentions that these can break and will cause problems. I will be ordering a replacement for about 12 bucks ASAP. I don't think this is the main issue with my starting. But, without it, I don't think I would ever get the engine working as well as it should.

 

[EagleNuke]

Re: 89 15hp johnson hard starting

Well, I got it all back together. Short on cash, so I made temporary fix for the cam roller by installing a piece of clear plastic tubing that is almost the identical thickness. It isn't perfect but will work for now.

I made a major adjustment to the linkage at trunnion ball. Leroys Ramblings has a photo of his adjustments on a similar engine, so I counted the exposed threads on his and adjusted mine the same. Figured this would at least be a good starting point. This allowed me to line up the cam mark with the cam roller. One drawback is that I see that the timing plate doesn't even go near the high stop even with the throttle at full speed...I wonder if this is going to cause issues at the top end.

I also replaced my wiring for the starter/charging after finding a wiring diagram. Now it is set up properly to charge the battery, and the starter motor turns at a more appropriate speed. Before, it was turning too slow so that the starting gear teeth would not disengage and remained stuck in the up position.

I covered the hairline crack in the carb top cover with blue RTV, this should be sufficient to stop any air leakage. And I set the idle needle at 4 turn from shut.

So, time to give it a shot, squeezed the priming bulb, pulled out the choke, pushed the start button....after a couple of revolutions it started right up.

As soon as I can get to it, I will run it in a tub and try to tweak everything in.

So, my next issue. When I went out to work on it this morning, I found the red button for the man overboard switch broken off and laying in the bottom of the boat. Looks like over a hundred bucks for a new switch assembly...so, I will have to figure a work-around for this now.