15hp Yamaha Enduro - Ignition Issues

[blahman]

Hi all,

I've just picked up a 2002 15hp Yamaha Enduro for a smidgen more than a song, but the catch is that it doesn't start! The PO put a brand new ($230!) carb on thinking the issue to be there, but the issue remains. He took it to a mechanic who tested around and claims to have determined the CDI is bad; the problem the guy had was he couldn't source parts here in south Florida. I have found a source for the CDI, but as it's $140, I'd like some other input. I know many folks on this board have these little engines, so I'm hoping someone can comment on my thoughts.


First off, as explained to me, the symptoms are that the motor will not idle, nor will it start without some form of ether or gas injection. Once running, if the throttle is kept up, it will run well - but you can't throttle back.

1) Does this sound like a CDI issue? I initially suspected low jets, but he just put a new carb on, and did calibrate it according to its instructions. I have not checked for spark yet, but presumably there would be very little?

2) How does one test a CDI on these outboards? I've been searching quite a bit and everyone says "test it as indicated in the factory service manual"...see #3.

3) Does anyone have a factory service manual he or she would be willing to share with me? I am having difficulty locating a manual for an "E15CMH" - "R" (aka, 2002). I can find service manuals for US 2-stroke 15hp motors, but not the Enduros. [Well, actually, I did find one...but it's in Finnish, which is not particularly helpful as I can't deal with that many vowels.]

4) Any other thoughts or comments? I can take our Perkins 4-105 apart behind my back, but this is my first outboard, so I'm not entirely sure where to start, especially considering I can't locate a service manual for this line.


Thank you for your time!
Aaron N.

[GordMay]

Probably more than you wanted to know, but check out
➥ Ignition FAQ

[Captain Bill]

There can be two possible issues with the ignition, spark strength and timing. To test the spark strength go to an auto parts store and get a cheap spark tester. The gap type works fine and should cost less that $10. If your spark is strong enough it will jump the gap marked CDI. The fact that the motor is able to run at high speed makes a spark strength failure unlikely IMO. In my experience a motor that will run at high speed is often an indicator of a vacuum leak behind the carb. The higher the speed the less time air has to leak in and dilute the fuel air mixture. I'm not familiar enough with the Enduro design to give you specifics on where to look, but I would check the carb gasket first.

Another possibility is that you have contaminated fuel or a bad fuel hose. If there are small particles shedding from the fuel line they can clog the low speed jets very quickly as they are very small in these engines. I once had the problem with an old fuel filter starting to disintegrate internally. I took the carb apart and found a powder like material had indeed clogged the jets. The engine still ran at high speed because the contaminants could not clog the larger high speed jets. If you take the carb apart you should see signs of contamination at the bottom of the bowl if this is the problem. You should note that the reason I knew it ran at high speed is because it started on starter fluid.

[blahman]

Gord,

Thanks for the link. I've just read through the article and, while it is good general info, quite a bit is geared toward constant-powered TCI systems (as the Yamaha VISION the gent is discussing has.)

Capt. Bill,

Thanks for your response. My initial thought on his description was that it was surely a vacuum or clogged jet issue as, when we used to have a waverunner rental business, this was a fairly common issue on our machines. I'm going to check the engine for spark today, and if there is good spark on pull, I'll move back to the carb. I'll certainly double check all of the ignition connections, too, as corrosion could create this problem. It appears the PO did replace the fuel line, and the course filter/RACOR appears clean (though, I understand that doesn't prevent clogging of small jets).

Thanks,
Aaron

[Admiral Cat]

Hello Aaron

I'm looking for the same, I'll let you know if I find one, could you do the same?
thanks
Alex

[blahman]

Hi Alex,

I haven't been able to find a service manual yet, however, I was able to locate a factory parts diagram.

'02 15CMH Parts Diagram
'03 15CMH Parts Diagram

I'm not sure if you're looking for a CDI, but if so, I found the part for my model (and likely most of the Enduros) to be 63v-85540-01, which is available online for about $120.

FWIW, I may not actually need a CDI as I was able to get the engine to fire, briefly, by reseating connections, so there may be a grounding issue that is rearing its face in the form of intermittent spark. These little engines are ridiculously simple, so there isn't much electrically to go wrong. The only electronic component is the CDI, which is barely electronic; most just a capacitor. Further reading has led me to believe that there is not really a method for determining if a CDI is good, but every model of a CDI does have a good method for determining if it is bad. The problem is that every one is slightly different, and I don't know what I should be looking for with this one in particular.

I'll let you know if I find a manual. Perhaps someone else will chime in, too!

~Aaron

[Admiral Cat]

Hi Aaron

thanks for that, I'm not after any particular part (yet), something is seizing so the rip cord is hard to budge, just trying to get to the bottom of it and hoping a manual might help

will let you know when I find one

Alex

[blahman]

Alex,

Hmm, is the pull cord only hard to pull? Once you get it out, does it retract easily? Once the engine is running does it run OK, without any apparent hesitation? If the engine runs fine and the pull-start is stiff on pull and retract, I think there is a good chance the nylon bushing around which the "drum sheave" rotates while engaging the flywheel is gumming up, or going bad.

I have the flywheel cover off right now and the bushing is obvious (Part #8 in Fig. 7 on page B5 of the 2002 parts list). A sailing school I worked for had some Yamaha 8's on a few keelboats and this bushing went bad on a couple, making the pull start really tough, while the motor ran great.

~Aaron

[blahman]

Alex,

Though I haven't found something specific to Enduros, I did get some useful info. A friend who has worked in a Yamaha dealership for a long while explained that there is little difference in the engine components between my 2002 Enduro and any other Yamaha 2-stroke from about 1984-today. He said they've changed some surface things, but that the CDI on my motor is the same one that has been used for twenty years. They've changed shape a couple times to accommodate chassis facelifts, but they're the same mechanical item. Some things are obviously different, for instance, my engine has two separate stators, whereas the shop manual shows a single. But the point for testing them is the same.

With that in mind, I started going through and looking at random parts sheets of different model/year 15hp 2-strokes and found that they almost all have the same CDI part number. That's to say, "XXX-85540-01" is the same across them all. The XXX is different, but my buddy said the first digits generally indicate a particular shape of the component.

SO, all of that said, I have been able to locate a shop manual for 1984-1991 15hp 2-strokes, and in this it details how to check my 85540-01 series CDI, and the rest of the motor. The carburetor and reed housing are different on my 2002, but as far as I can tell, almost everything else is the same.

Anyway, if you want the manual, shoot me an email.

Cheers,
Aaron N.

[blahman]

Hi all,

The short story is that the engine runs splendidly; the issue was in the wiring. Here is how I resolved this.


The first thing I did was go through and clean the engine really well using a home brewed engine cleaner (Boil some water, add a cup or two of washing soda, two tablespoons dish soap, one cup ammonia, spray on and wash off, scrubbing necessary areas). With the bit of soot and grease that was around, it was hard start with wiring issues.

As I was never sure the CDI was bad, having only the word of the PO, I began by removing and cleaning all the ground connections (there are all of about five...). Then I checked the CDI's connections. The CDI is right next to the fuel filter and there is supposed to be a wire binding that keeps the wires a couple inches away from the filter. It seems that a PO removed that wire tie at some point, so the wires have been close to the fuel filter. This would probably normally be fine, but the o-ring on the fuel filter was missing, so it seems there has been a sliiiight gas weep. So, as you can imagine, the heat-shrink bullet connectors that connect the CDI to the pulse, charge, and ignition coils have softened over time from getting gasoline on them, making all the connections supper iffy.

After getting the wiring temporarily set, the engine tried, reeeally tried, to run. But I found the carb was grossly misadjusted, with the throttle linkage set so that the linkage determined the idle rather than the idle set. Further, the low jet set screw was fully tightened, so the engine wouldn't run slow. I reset it all properly and, whalla!, the little thing springs to life on one pull and purrs like new.

When I get the engine to the boat where all of my electrical supplies are, I'm going to replace all of the bullet connectors with new heatshrink terminals. I'll be sure to keep them bound and away from the filter (which doesn't leak now...behold the magic of an o-ring), and I'm pretty sure all will be well.

FWIW, out of curiosity, I followed the instructions in the shop manual I found for the '84-'91 15hp that detail testing the CDI. It was real simple and the unit passed; in spec resistance readings throughout.




I guess this means it's time to make dinghy chaps and get the RIB rigged as our tender! We've been using an 8' hard rowing dinghy for a couple years, which works quite well, but it definitely limits one's exploring radius.


Cheers all!
Aaron N.

[Jim Cate]

Well done, Arron. These simple engines ain't even pizza science, and you don't need a degree in mechanical engineering to work on them. I hope that others can benefit from your experiences.

Cheers,

Jim

[Therapy]

Way to go Arron.

I was going to give my 2 cents but waited till the end to see what was what.

Good thing too as my 2 cents was worth ZERO!

Contrats!

[blahman]

Hi guys,

Bad news! I thought I had this little guy kicking, but it appears I was being fooled. I brought the motor back to the boat and set it up in a tank, then tried to get it running and it has the same issues originally present. As the wiring had been suspect before, I went ahead and replaced all of the connections. All done and the problem is still there.

So the CDI appears to check out, BUT that just means it is within its resistance specs, and some things I've read suggest that doesn't necessarily mean much. The pulse coil has the right resistance, and stator coils both check out, and the plugs give nice strong spark. Once in a while it will run very nicely, but only briefly (perhaps 30sec), then it'll go back to coughing and wanting to pass out like an emphysemic drunk. After these bouts of coughing (almost always ending in the engine dying), the plugs have a lot of oily gas on them, which goes to support that the spark is whacked.

So now I'm back to suspecting that the CDI is, indeed, bad. Or the timing is off, however I suspect the CDI more as, if the timing of the magneto were truly off, it would never run correctly. The episodes of it running perfectly (at idle, revved, in gear, etc) lead me to believe the CDI is sporadically messing up the timing. That said, does anyone know what the timing is supposed to be for these engines? I see timing marks on the flywheel, but don't know what it ought to be to check.

Alternatively, it could be the fuel pump. I removed the carburetor and reeds housing today to check their gaskets; they appear fine, so I reseated them (did not help). All of my messing was with the gas tank siting three feet below the motor, so perhaps the fuel pump is having trouble drawing the fuel up that far, although I doubt that as well as I did try "pumping the ball" a couple times when it started to cough, suspecting it wasn't getting fuel. I may try placing the tank above the engine, just to see.

Does anyone have an idea how I can tell whether there is an air leak around the carb/reeds housing gaskets? Soapy water?


Thoughts anyone?

Thanks!
Aaron

[Captain Bill]

A trick I was taught for checking for leaks in the carb gasket was to use a small squirt can full of outboard oil. Squirt it around the gasket. If the engine starts to smoke more than it did before you've got a leak. Also the oil temporarily seals out the air and the engine may run more smothly for a few seconds. The fact that it runs at high speed probably rules out the fuel pump. Another possibility is a head gasket. This is another situation where at high speed the leak does not have as much effect, but since the problem seems to have gone away at least temporarily this is unlikely. I still suspect the carb. I once had one on a four stroke that I disassembled and cleaned with every chemical I had at my disposal and it never helped. I finnaly gave up and took it to a professional shop where the guy soaked the carb in an ultrasonic cleaner for 24 hours, problem solved.

[Whimsy]

Originally Posted by blahman

... the CDI appears to check out, BUT that just means it is within its resistance specs, and some things I've read suggest that doesn't necessarily mean much. The pulse coil has the right resistance, and stator coils both check out, and the plugs give nice strong spark. ...

On a late 70s Honda 9.9, in about 1988, I had a similar problem with erratic symptoms and "fixes" that seemed to work for a short while, then the same old problems returned.

Was bringing a 33' "project" trimaran from Key Largo to NC. Mostly motoring up the ICW, but sailing outside on very nice days as the boat was in dubious condition for any serious offshore work.

Finally anchored in ICW in the town of New Smyrna Beach with completely dead engine, not able to legally pass under the next draw bridge under sail. Walked to payphone at a park, called Honda for ign coil test procedure and specs. Coil tested OK. Reassemble. Try engine. It runs a minute, then quits and won't start. Take it apart again. Coil tested out of spec this time.

Back to payphone to locate dealer with part - Boca Raton. Hitchhiked to Boca for part. Returned to boat to find my crew had found stone crabs in submerged terra cotta drain tiles and had a mess of claws - delicious!

Installed coil and no _ignition_ problems after that. Soon thereafter, the engine would run, then quit after a few minutes. Cover off, usual checks. Start engine, runs good. Put cover back on and go. Engine quits after a few minutes. Found that if cover were left off engine would run. Problem was eventually found to be corroded exhaust pipe from head had hole and was leaking exhaust which would choke down engine when cover was on - a problem common to that model.