unable to start '88 15hp Johnson

[deaston]

I recently acquired my first outboard motor, an '88 Johnson 15hp short-shaft with electric start. When I purchased it, I knew it had some problems. I'm somewhat mechancal, but I'm thinking I could be in over my head at this point.<br /><br />When the motor was purchased, it had the following known problems as diagnosed by a mechanic:<br /><br />- bad power pack<br />- broken cam follower arm<br />- leaking lower unit (water in oil)<br />- bad wiring harness on starter<br /><br />I verified that one plug was not getting spark and replaced the power pack - now getting visible spark on both plugs.<br /><br />I have replaced the broken cam follower.<br /><br />I have replaced the drive shaft seals in lower unit.<br /><br />I have replaced the water pump. <br /><br />After I couldn't get it started, I took apart carb and noticed that the idle tube was cut so I have rebuilt carb and replaced that tube... still no start.<br /><br />NOTE: It is completely possible that I screwed up one of the above procedures. I think I did it right based on my Clymer manual, but like I said, this is my first outboard. <br /><br />At this point, I can not get the motor to start. I have verified that pumping primer bulb on fuel hose causes plenty of fuel to flow to carb. I'm a little skeptical on whether fuel pump is pumping enough fuel (seems like just a trickle when pull starting) but I'm thinking priming should put enough fuel in the carb to at least get her started - is that correct?<br /><br />I have tried, although not with great deal of effort, to spray WD-40 into carb to get it to start. The only sign of life I've gotten is 3-4 loud bangs (backfire?) over the course of probably 100 pulls on the starter. <br /><br />I'd be happy to try anything, but maybe I just need someone to talk me into taking it to the mechanics...<br /><br />Thanks for any help!<br /><br />Dan

 

[fireman57]

Re: unable to start '88 15hp Johnson

First off, welcome to iboats. Secondly, don't spray WD40 in your carbs. Get a "windex" bottle and put some premix in it and spray that in the carb. You said that you have spark but you didn't say what color it is. Should be bright blue and jump a little over a half inch. When you had the carb apart I hope you soaked it a few hours or even better overnight in a good carb cleaner. After that blow all passages out with air and buy a carb kit for it and replace the parts. Kit should only run you about twenty bucks. If you have fuel and spark at the right time it should kick right over. You might check for a sheared flywheel key also. Compression check would be a good thing to do also.

 

[deaston]

Re: unable to start '88 15hp Johnson

I'm a moron... <br /><br />After re-reading my post, I remember reading something about backfires resulting from reversed plug wires.<br /><br />Sure enough, switched the spark plug wires, sprayed some fuel into the carb, and it fired right up!!!!<br /><br />Sorry to have wasted anyone's time with this, I have a new problem, but I guess that should go in a new topic.

 

[deaston]

Re: unable to start '88 15hp Johnson

thanks fireman... that's exactly what i did, however I used my wife's spray bottle she uses when she cuts the kids hair... now where to hide the evidence?<br /><br />Now the problem is that it won't start unless I give it throttle. I take it there is a distinctly different mode of operation at idle for a carb versus giving it throttle??? I can actually get it to start without the spray bottle now, but I have to give some throttle.<br /><br />I think I pissed the neighbors off... I really didn't think it would start!

 

[ob]

Re: unable to start '88 15hp Johnson

There is a slow speed idle air needle valve near the top of the carburetor assembly.Is it adjusted correctly?

 

[deaston]

Re: unable to start '88 15hp Johnson

The manual says screw it all the way in and then back it out 7/8 of a turn. Is that right?

 

[tashasdaddy]

Re: unable to start '88 15hp Johnson

don't start it with out it having water to it. common starting procedure: in neutral, pump bulb until hard, turn throttle until it stops. pull out choke or hold choke on elect. start. start the engine, release choke, lower to idle speed. you may have to bump the choke to keep it running until it warms up.

 

[fireman57]

Re: unable to start '88 15hp Johnson

Like tashasdad said don't run it out of water. If you did even if only for a few seconds go ahead and replace your impeller in the water pump. Run it in a trash can full of water. After it starts uses tashasdaddy's procedure let it warm up 3-5 minutes and then see if it idles when throttled down. If it doesn't then check the roller cam marks and see if they are lined up when throttle is all the way down. Might have to do a link n sync or adjust a cable if it is remote controls. Link n sync procedure will probably be found for your engine by using the red search feature at the top of the page.

 

[deaston]

Re: unable to start '88 15hp Johnson

Thanks for the tips. I am using muffs. <br /><br />I ran it for about 3 minutes this morning and it doesn't seem like there is any hope in it running with no throttle as is. It was running pretty rough too... a fair amount of vibration.<br /><br />Will check out the "link and sync" this weekend.<br /><br />...off to work.

 

[deaston]

Re: unable to start '88 15hp Johnson

Just to clarify, I can ONLY get it started if I put it in gear and give it throttle before pulling the starter (choke doesn't cut it).

 

[fireman57]

Re: unable to start '88 15hp Johnson

Should start easier in neutral. Sounds like your link nsync is off. Have you checked for a sheared flywheel key yet? The rough running seems to point me in that direction if the carbs are totally clean.

 

[OBJ]

Re: unable to start '88 15hp Johnson

Deaston.....try this....gently seat the low speed needle and then back it out 2 1/2 turns and then try to start it.

 

[tashasdaddy]

Re: unable to start '88 15hp Johnson

deaston, sound a carb or fuel supply problem. follow the fuel line to the black square with a srew in center, this is fuel screen. remove screen carefully, don't damage gasket. pump bulb should flood gas. clean screen, if this does not help then it's to the carbs and fuel pump. Joe Reeves has an extensive post on adjusting low and high speed screws. use the search function. everyone has good points here and it could just be one or a combination of all. it's going to have to start in neutral.

 

[deaston]

Re: unable to start '88 15hp Johnson

fireman - I have verified that flywheel key is not sheared (or at least it doesn't appear to be, but I didn't actually remove it from its grove in the crank shaft - looks OK though)<br /><br />OBJ - I have tried all different settings with low speed needle. Since it is running rough at all speeds makes me think there is another problem<br /><br />tashasdaddy - Pumping primer bulb sprays plenty of fuel out of fuel line before carb. I think I just didn't do a good job on the carb. I really didn't clean it out (although it really didn't appear to be dirty), just replaced idle tube and other rebuild kit parts and put it back together. <br /><br />My Clymer's manual doesn't say anything about the idle tube or show one in the diagram. In fact, I'm pretty sure I have a different carb than what is described in the maual. On this parts site, there are two carbs listed for my engine ('88 15hp Johnson)<br /> <br /> http://epc.brp.com/default.aspx?brands=ej&lang=E <br /><br />Anyone know anything about this?

 

[fireman57]

Re: unable to start '88 15hp Johnson

Are you still getting spark to both plugs? If so it is back to the carb.

 

[OBJ]

Re: unable to start '88 15hp Johnson

One carb was early production...that's the one with the rounded top. The other is late production...it has the flat plastic top on it. Which one do you have deaston. If you have the flat top and have rebuilt it, there is a chance the idle tube, that's the little rubber tube inside the bowl or the connections are still plugged. The holes are VERY small and can easily plug. Might check them out if this is the carb you have.

 

[deaston]

Re: unable to start '88 15hp Johnson

I have the carb with the idle tube (late production?) That's what started this whole mess. The idle tube was cut so I bought a rebuild kit. Replaced the tube but didn't do a thorough cleaning. Will clean thoroughly and report back.<br /><br />One more question. The rebuild kit I purchased had a LOT of parts in it, some of which weren't used. There were several gaskets in the bag. I assume I only use one for top and one for bottom and one for the connectoin between the carb and intake - correct? <br /><br />If you can point me to some reference info specific to my carb, I would be very greatful. The manual I have doesn't seem to cover it.

 

[OBJ]

Re: unable to start '88 15hp Johnson

The rebuild kits usually come with gaskets that will take care of a few different "style" carbs. Use the same gaskets from the kit as you took off the carb.<br /><br />Take a look at the FAQ section on the main forum menu. There is a really great thread there on 9.9/15's. Covers carb cleaning and rebuilding also. Just remember to make sure the idle tube holes are open. I take a can of carb and choke cleaner and hose them out good and follow up with air. When you install the idle tube, put a dab of TCW-3 oil on the end of the tubes. This will ease slipping the tube over the brass ends.

 

[deaston]

Re: unable to start '88 15hp Johnson

That site is excellent. Thanks!!!<br /><br />Cleaned the carb and now it runs MUCH smoother. Unfortunately, now I can't get it started without "priming" the carb with fuel mix before I pull start and I can't get it to idle (it just dies at low RPM). <br /><br />I'm certain I have a fuel leak (there was fuel leaking down the lower cowling) but I haven't figure out what that's from (it was pretty dark at the time).<br /><br />Question - How much fuel should the fuel pump pump? Its only a very small amount currently. Pumping the primer sprays out LOTS of fuel, but cranking the engine only gives a very small tricle. Would this cause the problem of not starting or idling, but running OK at mid-high RPM?

 

[fireman57]

Re: unable to start '88 15hp Johnson

If you unhook the hose from the fuel pump to the carb you can run the hose into a coffee can and it should put out a fair amount. When you changed the cam roller did you adjust (link n sync) everything back where it should be? Can you use your choke and start it? You need to find the source of your fuel leak that is running down the cowling before you do anything else.