CDI Bad?

The other Alex

The other Alex

(Jetdude)
Location
Lake St. Clair--
My ski hasnt run right from the start, and wont rev up all the way. It runs good on the trailer, but as soon as there is a load on it it doesnt want to start, and when I get it started it doesnt rev up all the way. I can pin the throttle, and it'll rev fine for a second, then it drops and feels like it's only running on one cylinder.
I checked all the coils with the ohm meter and they tested fine. The CDI is an old MSD from who knows when, so I was thinking maybe thats the problem. I have a stock CDI lined up, I am picking it up tomorrow, but Luke said it might be my coil anyway. I guess the coil can check out fine but be dead? I really want to get this fixed so I can get to FSF with a ski. Am I on the right track thinking its the MSD thats bad?
I got rid of the high compression head (210-Yikes!:bigeyes: ) and put a stocker, so compression is 140 in both with the mild porting. The carb was rejetted to spec and everything else is checking out fine.
My guess is either CDI, Coil, or crank seals.
If the CDI doesnt work, I have another carberator lined up to try, but I doubt its the carb, it runs to good on the trailer to be carb (i.e.-Its getting enough fuel).
Im just wondering if Im on the right track? And if I should plan to buy a new coil after the stock CDI...
 
WAB

WAB

salty nuts
Location
coastal GA
Have you opened up the wiring box to see if it's wet in there since it was sank?
The coils may have a broken plug wire or can not betting getting good connection to the plugs. It will crank up and run ok, but with highter RPM's there's more vibration, so it starts to break up. I had 1 or 2 do that and took forever to track down.
I'd check out the coil wires from where they exit the coil and strip back the wires a little at the boot end.
Make sure all the ground wires in the box are tight also.

When it's breaking up, how do the plugs look? Wet with gas? Maybe switch the plug wires to the opposite cylinders to see if you can get the same result with them switched.
 
The other Alex

The other Alex

(Jetdude)
Location
Lake St. Clair--
I havnt pulled the spark plugs, but the rear one was nice and hot, and the front one was warm, not quite cold, but not really hot. The electric box is all dry inside, surprisingly, and all the connections were good and also sealed, I went threw them the other night. Trimming the coil wires, do I have to trim them on the flywheel or just in the electric box?
 
WAB

WAB

salty nuts
Location
coastal GA
jetdude said:
I havnt pulled the spark plugs, but the rear one was nice and hot, and the front one was warm, not quite cold, but not really hot. The electric box is all dry inside, surprisingly, and all the connections were good and also sealed, I went threw them the other night. Trimming the coil wires, do I have to trim them on the flywheel or just in the electric box?
Click to expand...

Not THAT coil. The Spark plug's coil. The black plastic thing in the wiring box that the spark plug wires come out of.
First, I'd switch the plug wires to oppisite cylinders to see if you get same results but with front warm and rear hot. (it will not hurt anything)
There are members here that can help out lots more, but sounds like a coil issue to me.
 
The other Alex

The other Alex

(Jetdude)
Location
Lake St. Clair--
WAB said:
Not THAT coil. The Spark plug's coil. The black plastic thing in the wiring box that the spark plug wires come out of.
First, I'd switch the plug wires to oppisite cylinders to see if you get same results but with front warm and rear hot. (it will not hurt anything)
There are members here that can help out lots more, but sounds like a coil issue to me.
Click to expand...

Ahhhhh, got ya :biggthumpup:
 
Mouthfulloflake

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
Jetdude,

what is that in the pic of your avatar?

ive been staring at that for a while, and cant figure it out?

I see a green sunken ski, is it the tongue of a trailer sticking up?

what is the dude sitting on?
 
cookerq62

cookerq62

Life's Been Good
Location
Upper Bucks, PA
I had a prob similar to this. It would run fine just off idle but when you punch it it would misfire or run on one cylinder. I swapped out the coil and it was all better. It got progressively worse from bogging to misfireing to no spark.
 
M

MrSki

X
Kind of strange having a hot and just warm cylinder with a single coil. I had this issue with 2 coils and a total loss. One plug wet, other perfect. Swapped leads and problem followed so I knew it was a bad coil. I would guess on the spark plug boot end not connected right. Some of these use a screw in type connector - kind of a bad design. Eventually, the metal wire all arcs away and you are left with no connection. Pull the boots off and inspect.
 
keefer

keefer

T1
Location
Tennessee
Put your ohm meter across the spark plug wires. You shoud read about 4000 ohms if you have the stock NON resistor plug caps, 14000 with resistor caps. If you do not get a reading then you most likely have a break in the spark plug wires. Wiggle the wires while testing to make sure you don't have an intermittant connection. I have seen them break near the caps most often but also near the E box. If they are broken near the E box or too far back, you can have them replaced as opposed to buying a new coil. That being said, the coil can read fine but break down under the load of the high voltage. Test the plug wires thoroughly first before replacing parts. I would try the stock CDI next, as the MSD enhancers can go south if they get wet. Keep that E box dry.
 
The other Alex

The other Alex

(Jetdude)
Location
Lake St. Clair--
Everything tested out fine with the ohm meter. And actually, the reason the ski went down is because I lost power from the problem I am currently working on, and when I got towed the wave just started coming over the nose.
Surprisingly, the E-box stayed completely dry and all connections look good still.
As for the picture, the ski is sititng on the bottom of the canal in GainerA2582's back yard, I am hanging off the davit while his Dad cranks me up to grab a bilge pump.
 
The other Alex

The other Alex

(Jetdude)
Location
Lake St. Clair--
IceRocket1286 said:
nope, the hood is stock. i dont think alex was on it when it got towed, and it went down. either that or weighing 90 pounds didnt help lol
Click to expand...


Hey hey HEY... 120 :sneaky:

Well, the handle pole boot was off, the hood is stock, and I found a hole in the bottom of the hood about 1 in. tall by 1 in. wide, that didnt help. All that is fixed now, although the hood is still stock.
Even with me on the back of the ski, I couldnt keep the nose up, and then it went down, all I did was hang out to the tray and keep my head above water :Banane01:

When you guys say my coil- you are talking about the ignition coil right? The one that the spark plug leads go to...
Or did you mean the pulser coil, or the charge coil...?

Eitherway, I got the stock CDI today (thanks Uncle Hulka), I'll try it out tomorrow.
 
M

MrSki

X
Jetdude - did you ever check the boot ends of the plug leads? It sounded like maybe just a bad screw connection there. But by replacing the CDI coil (spark coil) you will be addressing the ends anyways...so you may never know if the original coil is still OK.
 
The other Alex

The other Alex

(Jetdude)
Location
Lake St. Clair--
I didnt replace any coils yet, just the CDI. I did pull the spark plug boots off the other day, when I pulled the enhancer, and trimmed the wires. I didnt try it yet though.
 
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