View Full Version : Electronic ignition change is great...kind of

05-21-2007, 02:29 PM
Over the winter I replaced the points in my '82 S&S (PCM 351W) with a new electrionic ignition kit. Simple switch by the way. After a slight adjustment to the timing it fires right off and runs beautifully...to a point. About 2400 rpm the motor bogs down, power is gone, rpm drop etc. If you keep the trottle there it will surge up to run at what seems to be proper rpm for a few seconds. I thought maybe I just had some crud in the carb from the winter so I tried to see if it would clear itself and it does not. It just continues to bog and surge. Once above 2400 rpm there is little change other than the rpm it surges to. This will happen with or without a load. (ie. does the same thing in neutral) As I said the boat runs fine if you never go over 2000 rpm or try to pull up a skier over about 75 lbs. I can cruise around like this all day.

I have run carb cleaner through the gas and cleaned the everything in the top half of the carb itself (I have an Edelbrock by the way). This has made no difference. I tried pulling our the EI in putting the points back in but I could not even get it fire.

When I did the conversion I removed the ballast resistor but did not replace the coil. I replaced that last year. It is a standard coil not a HO but the resistance measures well above the 0.6 ohm minimum listed with the EI conversion. I also replace the plug wires with a new 8mm set from Discount Marine.

I am now looking for anyone with something else to check.

05-21-2007, 02:52 PM
Since it will do the surge with no load or in neutral (or in the driveway), hook-up a timing light and see if the timing changes drastically at the 2400 rpm. Use a dwell meter to see what happens to the dwell time on the coil.
It may be EI coversion, but dwell time is still needed - it's just electronically controlled. Also, use a HEI ignition tester to see your potential spark output KV.

05-21-2007, 02:57 PM
If you changed coil before the conversion and replaced it with the OEM for the points setup, I would consider changing to the coil Skidim recommeends for the EI conversion anyway, see this thread, http://www.tmcowners.com/teamtalk/showthread.php?t=16464

05-29-2007, 01:46 PM
Okay, I upgraded the coil and still get the same results. I even tried to put the points back it but don't even get a spark with that.

With the EI I have the boat in nuetral on the trailer in the water. I can rev to about 3000 rpm before the tach sudden drops to about 1000 then starts to jump all over the place. The motor chugs and shakes violently. I can keep pushing the trottle up but it never gets better. Off of the trailer in gear this seems to happen about 2400 rpm but is basically the same. I pulled the plugs and they look nearly brand new. (I replaced the late last summer)

I am running out of things to look for.

05-29-2007, 02:08 PM
I would call, whomever you bought the EI kit from and get them to send you a new EI module that goes into the distributor and see if it corrects it. My kit had a bad module in it and all the engine did was spit and backfire as if the plug wires were crossed up, but the replacement module has been in it now for 5 years with no problems

05-29-2007, 02:10 PM
Got my kit for my "81" from http://www.skidim.com/ and have never looked back!!!

05-29-2007, 02:13 PM
Got my kit for my "81" from http://www.skidim.com/ and have never looked back!!!


05-29-2007, 02:34 PM
Talk to Vince, he will work with you I feel sure!

Guess I should of said it worked great and never had a problem

05-29-2007, 03:15 PM
Guess I should of said it worked great and never had a problem

:uglyhamme :uglyhamme :uglyhamme
Sorry, I didn't realize what I did! I somehow thought your statement was sbuell's thinking he was replying as to where he got his EI kit. Nevermind, I'm brain dead today!

06-11-2007, 01:10 PM
Okay, I new update. Now several weeks into the season I still do not have a working boat. I got a new electronic ignitions module. Still does the exact same thing. I have been through all of the electrical now and am out of things to replace. I did discover this weekend that my carborator is leaking fuel at the shaft for the secondaries. Seems to do it mostly right after I shut down. Since I can't have gas leaking on the manifold all the time I need to rebuild the carb. Anyone think this could also have something do do with the other problems?

06-11-2007, 06:21 PM
Just out of curiosity have you checked for total spark advance? Am I right in assuming the advance weights are re-used with this conversion? The only reason I ask is because I have experienced problems with the advance mechanism sticking thus not giving enough spark advance. I have also experienced broken advance weight springs, which do the opposite by allowing to much advance at low rpm's. To look at this you will need a timing light at least and one that has an adjustable advance would be ideal.

Just thought of something else to check...

Plug wiring routing, make sure they are in the correct (Firing) order. If you get just two out of order your engine will be down on power and vibrate some.

06-15-2007, 05:51 PM
Shot from left field- Sounds like it could be leaning out in when the secondaries start to open- it may have nothing to do with the EI conversion. Possible it's due to sitting all winter- floats stuck or internal seal leak. You said in a previous post there was raw fuel dripping from the throttle shaft? I would get a rebuild kit and start at it. check out this link for the owners manual for you carb: http://www.edelbrock.com/automotive_new/mc/carbs_acc/pdf/carb_owners_manual.pdf

Good luck and let us know how it works out:)

06-18-2007, 02:13 PM
If your boat's an '82, I'd say you're due for a carb rebuild...rebuild kits are obtainable from our good friends at skiDIM.