BigArm

So, I am fairly new to Sea Doo watercraft/boats, but I getting hands on experience and learning quite a bit from the forum. I have a 97 Challenger 1800 that has the usual "one engine keeps fouling" problem. In this case it is the port side engine.
Maybe I should back up a bit. I bought the boat this fall from a man who readily admitted it kept flooding one engine. The local Sea Doo shop recognized this boat and said, yes it has problems and keeps fouling the plugs in one engine after running for some time. I purchased the boat with this knowledge. Winter is arriving in Montana, so at this point I have only been able to check compression in the engines and put sta-bil in the fuel. Then I backed the boat into the local river and briefly ran the engines. Well, both engines run, compression in all four cylinders runs 138-145. Upon inspecting the suspect engines carbs, I noted the previous mechanic had left out several bolts here and there (bolts holding the intake sound suppressor and spark screen in place. Nothing noted yet missing on the carbs themselves; except the mag side choke butterfly was not clamped to the choke cable. When I pulled the choke, only the pto side choke butterfly closed. I tightened the mag butterfly to the cable and now they both close. Supposedly both engines would run for a while, then the port engine would load up and foul the plugs. Has anyone had experience, or could anyone give an educated guess as to the possibility of the mag butterfly being sucked partially or fully closed during engine operation and fouling that cylinder.
It seems to me that airflow though the carb body would have roughly equal pressure on either side of the butterfly and keep in open, but I really need to put the boat in the water and test it; something that will have to wait until spring.
Otherwise my winter projects include removing both tuned exhaust pipes and repairing the leaking plug on the bottom of both. I have seen great threads on this. I also will likely remove the offending carb and test it according to the manual. The 99 Sea Doo watercraft manual my parents have; which while addressing the same engine does not address the settings for the Challenger boats.
If anyone can give me carb model and settings for the Challenger, it would be helpful. Thanks, James

I am new to this forum and fairly new to Sea Doo PWC/Jetboats. This summer my parents purchased two 99 GTX PWCs and we enjoyed them all summer. I got a primer in maintenance during the winterization. This fall I purchased a 97 Challenger 1800. I have found reference to numerous maintenance issues in the forums and this boat will need some of them sorted out. One issue is a tachometer does not work. My forum searches indicate they are hard to come by and I found no reference to their repair. So I removed the offending tach and something was rattling about inside. I took a lucky guess and made an opening in the side of the instrument body with a 1mm diamond burr attached to a Dremel tool. The burr essentially melted the plastic and I then eased the flap away from the instrument body. The opening is between the 5500 and the 7600 rpm mark as seen in the pictures. I found a transistor loose inside and the old mount location was fortunately easily visible from the access I had made. In the pictures the transistor is the black and silver device on three "legs" next to the silver cylinder. I prepped the solder surfaces and remounted the transistor. I installed the instrument in the boat and fired the engine, and the tachometer works. Easy and cheap. James