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Trying to diagnose engine problem

Ronnie

Jetboaters Fleet Admiral
Messages
8,775
Reaction score
12,191
Points
667
Location
SF Bay Area
Boat Make
Yamaha
Year
2010
Boat Model
Limited S
Boat Length
24
I have a 2006 waverunner with a 998 cc, 140 hp, mr1 engine. It is the same engine found in the earlier 230 series boats. Over the last few weeks it's been giving me a check engine warning (light and sound) which would go away if I pulled the lanyard for a few minutes. My local shop ran their yds on it (for $106) and said the warning was a code 19 (low voltage) but the battery tested fine. To narrow the problem down would require a manual pin test for another $300 to $500. I know how to do pin tests for continuity and have an ohm meter so I decided to give it a try before dropping hundreds on what amounts,to exploratory surgery on my ski. This weekend it started when we checked it before launching but it would not restart when we got it to the ramp. This evening I switched out the rectifier but it wouldn't start, so a replaced the battery and it started easily so i ran it for 15 minutes on the hose. I figured I "fixed it", NOT! I couldn't get it restarted after that. Tomorrow I plan to replace the plugs and will more closely inspect the electrical system wiring and connections.
So the battery is good/new. The rectifier is also new. Other than a stator gone bad or corroded wiring any ideas on what could be causing this?
 
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When it won't start does it crank, click or nothing ? I can't make a connection on how pulling the lanyard would make any difference or the light go off, the ECU and gauges still have power to them?

I think I would buy a YDS and try to do your own test and check the voltages from the battery when it happens again, maybe a loose ground?
 
Could the kill switch be going out on you? Have you checked it closely for corrosion? I have heard of bad switches giving intermittent problems.
 
It turns over. I just replaced the spark plugs but it still won't start. It did start last night as I described earlier but that was the last time it did so. I will start checking the wiring tonight along with the starter solenoid, kill switch, coils and fuel injectors. I will probably end up getting my own yds system since it would be easier to diagnose this at home than trailer it to and from the shop over an hour away. Also, I'm guessing that the yds system will set me back less than the $106 it costs for me to have the shop use theirs. Thanks for the suggestions guys and please keep them coming.
 
Can you electrically disconnect the lanyard switch and then try to start the engine? The lanyard circuit is normally open contacts until the lanyard is removed and then the switch contact closes causing the motor to stop. When I bought my boat it had an intermittent failing lanyard switch. Once I diagnosed and found the problem, I ran for months without a lanyard switch electrically connected.
 
I may try that first as I looks like it will be a short day at work today. I should note that it likey was the rectifier that was the root cause of the low voltage alarm. I say this since prior to replacing it the battery would read 12v while the ski was running, after I replaced it last night with the rectifier from my other Waverunner (same model but with the 160hp 1,052 cc engine) the battery was reading 14.5 while the ski was running like it is supposed to, supposedly, and what the other ski was showing this past weekend. So it looks like I caused the hard starting problem or at the very least it is separate from the regulator problem.

I'm not looking forward to doing the pin test, so far the work has been easy because the regulator and plugs are easy to get to from the side of the engine, this is not the case when the engine is installed in a conventional hull. However a lot of the wiring is on the bottom sides of the engine and there is almost no space between the engine and ECM, this makes it touher to get to than it would be if it was installed in a boat.

At least the lanyard is on top so I will start there before diving into the rest of the wiring. I enjoy the challenge and hope to resolve the issue before my next camping trip at the end of the month but if I can't I may just call it the end of the season for the skis and drop them both off at the shop. Wait for the diagnosis and decide if its worth fixing based on the current Market/nada value of the ski compared to the cost to repair it.
 
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I was about to check the lanyard but thought that since the engine turns over and gauges light up when it is in and I hit the start button that it must be working. Am I wrong about this?

I also sprayed some wd40(aka jet skiers best friend or ghetto starting fluid) down the intakes but it still wouldnt start, just crank. Now I'm thinking I'm not getting spark from the plugs. I will check that next, easy enough and I should have done it while I was replacing the plugs this morning. Thoughts?

I was a little disappointed to find that I don't have the shop manual for this ski, just the owners manual, the trouble shooting section of which says take it to the dealer for my problems. Great.
 
Attempting to start the engine without the lanyard in place on my boat will still allow the motor to turn over, but it disconnects the ignition. So it could be your issue if it turns over but you're not getting spark. It would be a simple find with the YDS system. Try exercising the switch several times, reinstalling the lanyard and then attempting to re-fire it.
 
Aug. 15th AM update: I just checked all of the fuses and visually verified that I am not getting sparks out of any of the spark plugs. I will test the lanyard kill switch next and may just move the one off of my other waverunner to do it. I am hoping and praying that this is the problem because the alternatives are much more time consuming to identify and expensive to resolve.
 
@Ronnie @itsdgm is correct about the lanyard. It only kills the ignition. Your problem IS electrical so I believe you're on the right tract. I believe your problem is either the low voltage side or the high voltage side of your ignition. If you have or can borrow an inductive timing light or low cost inductive ignition tester you can see if any power is going to your spark plugs. If just one coil is not firing that can cause an MR-1 to not start. I had this same issue. If you are getting a light @ each coil that also proves out the low voltage side of your ignition. If no light detected at your coils you need to chase down the low voltage (12v) side of your ignition circuit from your battery, through your ignition & lanyard switces to your starter solenoid.
 
Ahhh, just got your update. So, it is the low voltage side of your ignition circuit. Good find. Your lanyard switch can be bypassed (shorted out) to test. If not that your ignition switch.
 
Food for thought, I have had a similar issue with the throttle positioning sensor. Every so often the engine will turn over but no spark, I snap the throttle hard and release it several times and the engine starts. This happens occasionally. The computer is set not to fire if the throttle is not all the way down to it's slowest idle setting. Perhaps you have some dirt or corrosion in the throttle body causing the butterfly not to close completely and the sensor is telling the computer not to give it any ignition.
 
I paid $75 for YDS on eBay. It does have some diagnostic tests but I'm not sure if those will help here as I didn't really look into them much.
 
Aug 16 AM update: It's not the lanyard switch, the one from my (working ski) did not resolece the problem either. I also verified that the throttle is going all the way to the stop. i tried jiggling the lanyard, snapping the throttle and hitting stop a fee times as well. I have already ruled out the battery although replacing the rectifer may have resolved the check engine warning 19 (low voltage) issue i am still not getting any spark from the plugs.

I will order up the yds tonight as long as i can use it without the enfine running. While im waiting for it i will continue to trouble shoot, next i need to located the ignition coil(s). They are probably in the dreaded vault that i will need to remove to get into. Looks more loke pandora's box too me.

Thanks for the suggestions so far. Any other thoughts?

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Aug 19th AM update:

I cleaned off and tightened the battery connections and verified that all of the other connections are tight but I'm still not getting any spark so the engine turns over but won't run.

I also dismounted and opened the "vault" with the ECM in it and was disappointed to find some water in it. Not much, maybe some of it drained away before I opened the box, but it did allow one of the components in the box to get wet. It's the silver and black thing in the pic, the "slant detector". I opened it up and it it is fine.

Misc. note: I suspect that the negative cable to the battery maybe loose or corroded but it leads under the engine so I'm having a hard time checking it. At the same time I doubt this is causing my no spark problem in that the engine turns over fine.

Without a yds system or shop manual I feel like I'm operating blind and don't want to cause more problems than I already have so this is going to have to wait until the off season for me to resolve. It's official, this ski is done for the year.

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@Ronnie. You mentioned possible ignition coil/coils. Does this not have the same ignition coil set up as my 2006 MR-1 where there is a coil on each spark plug? If that's the case I can't believe all 4 coils are bad. Can you get a spark plug tester which will prove the coil working or not? http://www.summitracing.com/parts/r...zR7IQbPdsOh-gGIWMFp6BVvzJCLBigXGOyRoC743w_wcB

It still sounds like the low voltage (12v) side is the problem unless you have a single ignition coil for all four cylinders.
 
@Gym , you are correct the shop manual excerpt I was reading was from '03, I hiss before they went to A one coil per plug system. Since everything worked (I got the engine started on a hose for 15 mins after switching out the battery and rectifier) I'm having a hard time believing her it's the coils either, one maybe but all four at the same time, Beth doubtful. I'm switching my focus to three remains items:

1 a loose or corroded ground connection (hard to verify because It routes from the battery than under the engine).
2. The stater/ignition relay in the vault ( I have not figured out how to test this ( but the connections are good ).
3. The ECM (If this is dead this ski is probably done).

The last time a wanted. / needed this ski was this weekend so I will take it home and try a little more trouble shooting , if I can t figure it out ill bring back to the shop and let them know what I ruled out, maybe this will save me on the disgnostic fees. I've already spent at least 4 hours trying to figure this out so I've gotten a several lessons In pwc inner workings as well as patience.
 
Bad news, tonight I found water in the oil and water coming out of cylinder 3. So I Cranked the engine until no more water was spraying out of cylinder 3, Fogged the cylinders and started removing the oil.

My retired mechanic neighbor said he'd supervise if I wanted to take this on myself. I'm going to look at all my options before determining what's next but having visited the local pwc dealer today I know buying a new one for about $15k out the door is not an option.
 
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Bad news, tonight I found water in the oil and water coming out of cylinder 3. So I Cranked the engine until no more water was spraying out of cylinder 3, Fogged the cylinders and started removing the oil.

My retired mechanic neighbor said he'd supervise if I wanted to take this on myself. I'm going to look at all my options before determining what's next but having visited the local pwc dealer today I know buying a new one for about $15k out the door is not an option.
Sorry to hear about the water @Ronnie. Does your old machine have a trade in value towards a new machine? Possibly another MR-1 engine from a damaged ski machine may be options.
 
That's terrible, sorry to hear that @Ronnie. Sounds like you have the ability and help available if you decide to fix it.
 
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