Engine quit suddenly after running perfectly.

[fireman57]

Re: Engine quit suddenly after running perfectly.

You say flywheel key is fine but can't check if from work. Have you visually inspected it yet? Do you have a OEM manual or are you just shooting from the hip? An OEM manual will help you find out step by step what to check. It will also give you tips that will help you bypass things that need not be checked. It is a very worthwhile investment. It seems like people are trying to help but you provide vague answers. examples being, how do you check spark without being zapped but you say spark is fine, how do you check for spark with a timing light when it will not spark. The timing light will show spark even if the engine is not running. The last example is Upinsmoke asking again for an answer that was not given regarding your compression. I am not trying to flame you in any way shape or form but you need to try the things that these experts (include me out) are trying to get answers for so they know where to look next to get your problem solved. I know that the "regulars" will keep following this post to help you but you have to do your best to give them the information that they need to make an educated guess.

 

[calm like a bomb]

Re: Engine quit suddenly after running perfectly.

The flywheel was checked yesterday.No problem found.I have had the owners manual for this engine for ten years.Believe me,I know how to check the fire from the plugs against the block.I have never really known about getting it to jump 1/2" from the plug boot to the block.Anyone with any common sense would want to know how to avoid gettin zapped yet still have a way of holding the plug boot at a distanceof 1/2" for the test to be effective. <br /> A check on the sparkplug fire and the throttle linkage was what I was refering to when I said it was hard to check from work.Not the flywheel key.<br /> I also asked if it was possible to use a timing light when the engine will not start,I never said it had no spark.I stated The compression readings I did not post because it was many hours before I saw the request for them.I do not get to monitor the forum at all times.<br /> i stated in the first post that the flywheel was fine and that the engine provides spark and that I had tested it.Nothing vaque about the information provided.I am simply trying to determine what the problem is as best I can.Sorry I did not do it to suit your taste.You may want to start at the beginning of the thread..you will probably find that I have provided as much detailed information as I could.

 

[calm like a bomb]

Re: Engine quit suddenly after running perfectly.

upinsmoke,<br /> Sorry for the delay on the compression numbers.I know you guys are trying to help and I do appreciate it.Compression numbers follow:<br />Top cylinder=115<br />Middle=120<br />Bottom =115<br /> <br />Also..I love your idea about the test rig.That will have to be done in the morning due to work and I'll post results.Thanks again to everyone for your help.

 

[G DANE]

Re: Engine quit suddenly after running perfectly.

You wont get zapped - I usually just hold boot by hand, and put a nail in boot and hold the nail 1/2" from block. Start with something less that 1/2" to see what it actually can manage, then increase distance. The spark will rather jump to iron/aluminium than your hands. If you get Zapped - no big deal, just uncomfortable, dont be a chicken, unless you have a pacemaker, nothing will happen. If it sparks somewhere around the time needed, and the spark is strong enough to jump thru the fumes in combustion chamber, not in open air ( thats why we test at 1/2 " gap outside ) it will pop at least.

 

[calm like a bomb]

Re: Engine quit suddenly after running perfectly.

G DANE,<br /> Good deal..that's a really good test you guys have..seems like the entire world knows about it but me.<br /> I don't know if I'm chicken but I sure do remember getting lit pretty good from the coil on my old 1978 Datsun 280-Z.<br /> I could not start it and was determined to see if the coil had failed..it was still good!!

 

[calm like a bomb]

Re: Engine quit suddenly after running perfectly.

Curiousity got to me after work and I just determined using the "clothspin test" that about all the spark jump I can get is about 1/8".<br /><br /> Not nearly the 1/2" you gentlemen suggest.<br />Electrical for sure..next step?<br /><br />1. Check timing?<br />2. Ignition pickup coil?<br />3. Get in the old wallet and buy a new powerpack?<br /><br />Thanks to all who have helped in this drama.

 

[fireman57]

Re: Engine quit suddenly after running perfectly.

Sounds like a bad powerpack. See if you can borrow a used one from a buddy and try it. Maybe the dealer might have a used one laying around you could use for testing and then buy a new one from him.

 

[calm like a bomb]

Re: Engine quit suddenly after running perfectly.

fireman57,<br /><br /> That's sure what it is starting to look like.Weak fire about 1/8" was all it will produce now.I wonder why it would fail so abruptly though. <br /> I don't know anyone with the same engine so I hope the dealer can test it with a known good unit.it's a shame because it ran good up until it conked out.<br /> I still would worry about it happening again even with a new one,unless I can determine why the old one fried itself.Maybe it was just time for it to go.

 

[fireman57]

Re: Engine quit suddenly after running perfectly.

You might try cleaning all your grounds to it. Strange things happen with powerpacks. Sometimes they start going out at high speeds and sometimes go out all at once. The dealer should be able to test it. Takes special equipment.

 

[Max7]

Re: Engine quit suddenly after running perfectly.

tried www.Ebay.com and click on Ebay motors you will find a use one

 

[Max_Door]

Re: Engine quit suddenly after running perfectly.

I am a beginner myself, but I had an experience repairing mine that sounds like this. I thought I had a hot spark on both cylinders, but would not run. Learned that under compression, it was shorting from the faulty coil to ground. Had me fooled and frustrated for some time.

 

[G DANE]

Re: Engine quit suddenly after running perfectly.

I had same problem, only on a twin 35 HP. Suddenly quit and almost impossible to restart. Turned out to be corrosion on pins in the Amphenol connector ( rubber connector ) between the charge coil under flywheel and powerpack. I would start there if I were you ( which I never was and will never be ) . Next check all ground . prone to corrode. If powerpack is fried, often only one spark will suffer.

 

[calm like a bomb]

Re: Engine quit suddenly after running perfectly.

The Amphenol connection was the second thing I checked,after the main fuse.They were both corrosion free.<br /> I'll check all grounds again but right now the spark is weak from all cylinders,about the same weak 1/8" jump from each one.Not nearly enough according to the gentlemen on this forum.They are correct because it is dead as a rock as far as starting.<br /> I stated on the other post that I will probably drag the corpse to the dealer tomorrow.Thanks to all for your help.I'll let everyone know what the end result turned out to be..other than my wallet getting lighter

 

[fireman57]

Re: Engine quit suddenly after running perfectly.

Sorry we couldn't get it done. If you have weak spark to all cylinders now I doubt it is a pack. Make sure you do post the solution on both of your threads. If this ever comes up again (which I'm sure it will) we will know what else it could be. Too bad you have to be the guinea pig.

 

[rodbolt]

Re: Engine quit suddenly after running perfectly.

hello the pack does not amplify. its just passes on what the stator feeds it when the triggers triggers it. its a simple suck,squeeze bang and blow. if you have fuel/air, compression, spark at the correct time and exhaust it runs. dont care if its a model T, a northstar or a 70 jonnyrude. your radically over complicating things. I have had the ground stud on the exhaust cover corrode. when it does you have to physically remove and clean then reinstall the stud. were it me I would isolate the black/yellow wire from the pack and retest. thats why I have a spark tester, a CD-77 meter and some other cheap test equipment.

 

[Basscat 1]

Re: Engine quit suddenly after running perfectly.

He is getting spark, but as somebody mentioned before, is it at the right time?<br />Example; piston 2 comes up on compression, but piston 3 sparks.

 

[calm like a bomb]

Re: Engine quit suddenly after running perfectly.

OK guys....I drug it to the shop today.Thanks to all who helped..I'll let everyone know what the culprit was when I get it back (10 to 12 day waiting list) I'm taking one of my other boats fishing until this one gets revived.I still think the fullmoon did it on Friday,March 25th when it died on me.

 

[Lowranger]

Re: Engine quit suddenly after running perfectly.

'89 Johnson. 1500 hours. This happened to me twice. @ 45 hours it was a bad powerpack. @ 1100 hours it was a stator. This one challenged my techs. It bench tested to specs but would'nt start.

 

[Freezebear]

Re: Engine quit suddenly after running perfectly.

Sure hope you find out what is wrong. Mine is acting the same way, but I can get it to fire and run very badly at high Rpms by advancing the timing. I too think it is some sort of electrical problem too.