confused...HX doing the puff daddy remix!!!!

[josh42575]

after spending all summer tuning in my hx. put a new engine in it finally got it screaming across the water but now its doing something i cant figure out!!!

on smooth water it runs strong and fast. get in to some chop and the engine coughs almost like it skips a beat but comes back right away... it almost sounds like a record scratch (puff daddy remix) lol. new engine. compression 135 on both cyl. perfect idle. again. it runs great except for the skip. i checked for cylinder slap on the plugs, good clearance. it almost sounds like pre-detonation. also... engine mounts tight. cant find anything loose!!!!!!!!!!!!!!!! HELP!!!!!!!!!!!!!

 

[seadoosnipe]

Rev's

If it runs out smooth on the glass, then do you think maybe in the rough your hittin the high rev's and the limiter is dropping a cylinder to keep it from going over?..........just a thought.

 

[josh42575]

i questioned that, however when you get it airborne it hits the rev limiter without coughing like it does, also i dont have to be at full throttle, just higher up in the rpms. but it definetly sounds like a cough. or a scratch but power comes back instantly. thank you though. ive been brain storming. checkrd the fly wheel and behind it to see anything loose but to no avail

 

[seadoosnipe]

Plugs and coils

You may have a weak coil. I'd also look at the gap on your plugs. If your engine is running well at idle and you get smooth operation at higher rpm's, I don't see where this can be a carb problem. Sounds like it's gonna be in the coils or plugs, maybe the resistance in one of your plug wires is breaking down on you........I don't remember the exact year you said it was, but if it's in the 90's, then it's real possible it's resistance in either a coil or the plug wires. That's kinda gettin out there for me, but I can't think of anything else. There is a test you can do with a standard electrical meter that you buy at a local parts house to trouble shoot this stuff with. Although I've read it and it seems like the steps are real easy to follow, it would be way to hard to describe it to you in this forum. You'd really need to read the chapter in the electrical section of the manual to understand it better.
But I'm pretty sure it's not going to be a carb. And I don't think it's your MPEM and I don't think it's one of your major electrical componets. I just feel like it's probably in your coil, plug or wires.................

 

[josh42575]

that is a good idea..... i wish there were a way to see if it was misfiring or shooting flame out the carbs like poorly timed ignition. its wierd that it would only do it in slightly rougher waters but it doesnt take much. on glass, smooth as glass. a little chop, whooping cough. thanks, ill look there next.

 

[seadoosnipe]

Timing?

If it's smooth on idle and smooth at top end and you experience a hiccup midrange or while the ski is jostled around on rough seas, then I wouldn't think timing. It may even be possible that you have a wire loose somewhere. Like a ground wire. Hard to know. You have several things you could check.

 

[josh42575]

I Had Hoped I Could Find A Loose Wire Or Something In The Flywheel To Be Causing A Misfire But Nothing There. Pulled The Coil Box Apart. Nothing Wet And All The Wires Look New. Checked The Ground Wire At Battery And Block. Again, Cant Find Anything Loose. It Only Does It On Top End But Not Necessarily At The Very Top Just Close To It. Only A Couple Of Nice Days Left Here According To The Weather Channel. If No Luck Then Off To The Dealer We Will Go. It Has Always Sort Of Done It But It Has Only Been Recently That Ive Been Able To Get This Thing Out To The Water And Have It Run Really Well. Before It Wasnt All That Fast, Lots Of Exhaust Leaks, Carb Troubles, B.s. Things That Seem To Trouble Everyone. Rebuilt The Carbs, New Gaskets, New Plugs, And Some Tlc Later, Holy Crap, It Doesnt Even Feel Like The Same Ski, But This Problem Has Gotten Progressively Worse The Stronger I Made The Ski...

 

[JPX]

I'm thinking electrical as well - either from impact where a loose connection becomes more apparent or some sort of current limitation from something that is firing weakly.

Plug wires can look new from the outside, but might have corrosion on the wire tips where they enter the plug boot.

Same thing with the ground wire....might need to cut off a section of the wire and install a new clamp/lug. Or even replace the wire with a new thicker gauge cable.

 

[josh42575]

wierd huh?????!!!!!????? pretty sure its not the plug wires, trimmed off about a half an inch when i replaced the engine. and have regularly checked to see if perhaps the connection between the boot and wire is good (mostly because im anal almost to the point of being O.C.D. about my skis. but a loose wire sounds like a good culprit. or a coil. at first i thought it was something grinding because it sounded like if you take a piece of sheet matal and quick struck it across concrete but the more i brain-storm, with help from you all of course, it sounds like a misfire, any one know the gap measurement for the plugs?

 

[seadoosnipe]

Plugs?

Your plugs should be the NGK BR8ES with a gap set at .5-.6 mm (.020-.024 in.)
Your plug wires are a concern, although I wasn't able to find the infomation I was looking for to prove my point. In general, plug wires conduct electricity by a carbon fiber element inside the insulated part of the wire. Over time the flow of such a large amount of voltage can break down the resistance in the wire. This can cause a lower voltage at the plug itself. I almost think it's only one of your plugs and/or wires. If there is a potential problem in the wire, you may be able to gage it by pulling both plugs and while leaving the wire attached, lay them down across the head and roll the engine over (you may want to be in a dim lite area to see the spark). Look to see if the color and intensity of the spark are the same on both plug tips. And of course, you know I'm sure you know, not to touch the plugs while doing this.

 

[josh42575]

nah, i have a trained monkey friend who holds the plugs for me while i turn it over. lol.... thanks, ill check that

 

[Wheels & Waves]

The next time it starts stuttering on rough water, pull the choke partially out and see if it clears up any. This would tell you if it is fuel related.