need some help

[sjetrider]

My sons boat is a ported 701 w/
ADA head 33cc domes 205 comp. (just changed from 35cc since last ride)
MSD enhancer (just installed from my boat since last run)
Riva Alum flywheel (just installed from my boat since last ride looked fine)
B-pipe mod chamber dual water (just added dual water since last ride)
twin 44 Mikunis 110 pilot / 120 main 1.8 n/s (21psi pop off) (carbs are like new but have been run before like 4 years ago, I just bought them and added new n/s and jets) They look new inside and out.
Riva mnfld w/ no spacer, pro series boyeson 2 stage reeds (same set up as before except I removed spacer)

My problem :
Runs great and crisp on trlr and for about 2-3 mins. in water. Then it turns to CRAP running like it is on one cylender. Let it sit 2-3 mins. and it runs fine for 30 feet then accurs again.

I thought it could be reeds as I saw some smoke coming out of rear cylender, I removed mnfld and rear read was hung open like 1.5mm but in good shape, I flipped read over and seemed fine so I reinstalled. I was also sceptical of the enhancer so I changed it back to the OEM modified CDI. I OHMS checked stator wires, plug wires and coil wires (all seemed fine).
I took it back out and it did the same exact thing as above.

Last night:
I removed the head to inspect and replaced compression O-rings (cylenders & pistons look fine), rechecked compresion and was @ 205 rear 208 front. Put the Enhancer back in and double checked all w/ ohms meter again, decided to change the coil even though it Ohm's tested fine (figured it might be getting hot and breaking down). I emptyed the gas tank to check for water (near none), chanded the check valve (even though it seemed fine), changed the fuel filters (just in case) and double checked pop off on carbs (checked fine). The spark is excelent and plugs are brown and seem dry.
Boat once again runs fine on stand.

Anything else I should try before I test ride tonight? I am supposed to leave for Orange Beach Friday after work and need this boat running and I only have time for one more test ride before I leave. What else can I check, has anyone had this issue in past???????????????????

Any and all help appritiated.

Sincerely,
Desperate in 615:dunno: :17: :17: :17: :17: :17:

 

[SuperJETT]

You've done the things I would have done.

The last 2 things for me:
stator, even if it has good resistance readings, heat can break down the insulation and cause problems running
fuel lines themselves, I've seen some deteriorate inside and cause blockage, or have something lodged inside that didn't make it to a filter or the carbs.

 

[parrdaddy]

I would try riding the ski with the check valve and line off the tank, so it is open to atmosphere. It sounds like your not getting air in the tank and sucking down to a vaccuum in the tank. If that doesn't fix it, at least you can completely rule it out without throwing money at it.

 

[uga86]

My ski did the exact same thing last year on my first trip after putting in an enhancer, b-pipe and prop over the winter - it ran great for a couple of minutes then it felt and acted like the overheat sensor kicked in ( felt like running on one cyl, etc ). Put it on the trailer, look things over, put it back in the water and the same thing - ok for a minute or so then crap.

I tested the overheat sensor per the manual and it checked out ok so I took out the new enhancer and put the stock cdi back in and the problem went away.

I had the enhancer bench tested by JSS and they didn't find anything wrong with it, but I've never put it back in.

Edit: Just saw you already replaced the CDI - nevermind...

 

[sjetrider]

I will definateley run w/o check valve to test. Blowing in check valve both directions it appears to function correctly BUT who knows.
UGA86, I thought the same as you on the Enhancer, but when the OEM CDI did the same I ruled it out (but could be both doing the same thing).
I instantly thought the overheat sensor myself, but I have it disconected and run the same as always. ?????????????????????
Please keep IDEAS coming.

 

[sjetrider]

Hey Darin,

I checked the fuel filters in the carbs/pumps and they are spotless. The return lines seem to be staying loaded with fuel. This is the Hot Products clear blue fuel line and I do not see any visible blockage but changed the external fuel filters just in case.
Do you think it is worth replacing fuel line just in case as well?

You've done the things I would have done.

The last 2 things for me:
stator, even if it has good resistance readings, heat can break down the insulation and cause problems running
fuel lines themselves, I've seen some deteriorate inside and cause blockage, or have something lodged inside that didn't make it to a filter or the carbs.

 

[sjetrider]

Another change I made was removing reed stuffers and spacer plate between Riva manifold and cases. I was thinking this would improve bottom end response with quicker and better signals to carbs ??????? This was a trial thing based on Waxhead and I think Mark44???:dunno: findings. Could this cause an issue? I have always run this motor with stuffers and reed spacer in past w/o issue, just thought I would try something new.:banghead:

 

[Big Kahuna]

have you checked the plug wires.............

We just changed Chris's stator in Blue, it went south, started running bad then no spark.

 

[sjetrider]

have you checked the plug wires.............

We just changed Chris's stator in Blue, it went south, started running bad then no spark.

Brand new plug wire w/ MSD boots testing at 4.68 OHM's and back side of coil testing at 3 OHM's. The spark is awesome, it actually jumps out of end of boot.

 

[norcal ex]

could the exaust gasket be leaking and putting water in the cylinders?

 

[DAG]

i have a simmer problem last summer, b/c of a bad connection/broken plug wire... with the engine rattle the wire would randomly connect/dissconnect

 

[sjetrider]

could the exaust gasket be leaking and putting water in the cylinders?

This is poss. I thought it might have been the O-rings in the head doing just that and replaced them, but I did not check exhaust gasket. I will do so though. :biggthumpup:

Please keep them coming.

 

[sjetrider]

One of the above thing I changed fixed the problem, dont know which one, but one of them did the trick.
Thanks for all your help.

 

[Shonuff]

I wonder if you had exhaust gasses building in the bilge and choking the engine.

How do you have a son old enough to ride? I've met you, you're like 25 years old????

 

[Jawbreaker]

How do you have a son old enough to ride? I've met you, you're like 25 years old????

Your making his head swell.:haha:

 

[YAMA CAT]

I wonder if you had exhaust gasses building in the bilge and choking the engine.

How do you have a son old enough to ride? I've met you, you're like 25 years old????

You're in TN Now, They Marry Young:biggrin: :biggrin: :biggrin: