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[Hydro_Therapy]

Hello sea-doo gurus!

I have a 1997 Sea-Doo Challenger 1800, twin 787s both replaced in ~2008. When I got the boat (last season) the stbd engine ran fairly well, and the port didn't run worth a damn. Both engines have 145-155psi compression, I've rebuilt all 4 carbs, (mikuni kits) pop-off is ~30psi on all four, High and low speed adjusters set to spec, idle set to ~3k out of the water and settles nicely around 1500 in the water, trimmed the plug wires on both engines, drained-cleaned- refilled oil tank, drained and refilled fuel tank, checked oil delivery, adjusted pump, adjusted both throttles (dock assist too) everything seems good. port engine idles a tad rough, but both run well now- full throttle application results in a fairly brisk acceleration to a little over 7k rpm on the factory tachs (fairly close to my digital 'tuner tach') and the boat quickly jumps on plane and accelerates to around 50mph on the dreamometer. Couple issues; when pulling a tube with two teens on it, port engine went to 5k at full throttle, stbd went to 7k. when we crossed some wake and the port engine encountered air (unloaded briefly) it accelerated to 7k and remained there until I pulled the throttle back a while later- the kids were enjoying the added speed(question is- why wouldn't it accelerate until it was unloaded?). My second issue; when we stop for a while (or I 'kill' the engine by accident) the port engine will start right back up unless we wait more than 15min or so- then I can NOT get it to restart until it cools completely (HOURS). Finally, the plug wires on the stbd. engine appear to have a true metal core like racing wires used to have, but the port engine has the carbon looking core which is right?

So to restate my questions:
1: Suggestions as to why the port engine wouldn't reach WOT rpm until it was 'unloaded'?
2: Any idea what might cause the 'no restart' issue when the engine is good and warm?
3: Can the plug wires be replaced independent of the coils? What type of wires should I use (would automotive metal core performance wire be ok)?

Thanks in advance, I'll get some photos of the boat up soon (along with my dual-battery install project).

 

[LouDoo]

I would start by replacing the coil and wires on the port engine. As far as I know you will need to replace the wires and coil as a unit and the stock spark plug cables have a copper wire core. Also when were the rave valves serviced?

Lou

 

[Hydro_Therapy]

Thanks Lou! That is kinda where I was headed but really wanted to hear from someone with more experience!
I knew I'd leave something out lol- raves serviced on both engines as part of getting it up-to-par early this season (removed, cleaned, replaced one diaphragm and two 'clamps', new O-rings and gaskets). I adjusted them per one of the other threads (number of turns out escapes me at the moment) and backed the port engine raves an extra two 'clicks' because it'd accelerate to about 5k and hang then surge to 7k really hard and abruptly- 'loosening' the raves seems to have cured that- I can still feel the surge when they open, but it's just a tad earlier and a LOT smoother. Starboard engine raves open around 4k to 4500 ish and it's noticeable but not harsh.

As for the wires- my port engine has what appear to be standard automotive 'carbon' core wires- one of the parts guys in here said the wires 'can' be replaced but it's a PITA- I have a source for regular copper cored performance plug wire locally, I will give the wires a shot first and keep you posted!

 

[LouDoo]

I've tried, without success replacing just the wires. There's a small plastic retaining clip that holds the wires inside the coil. It's just about impossible to remove the clip without breaking it.

Lou

 

[Hydro_Therapy]

Well fun! I guess since I've confirmed the wires are probably wrong- it's possible they've been altered preciously- haven't looked real close inside the electrical box yet- maybe I'll find something out-of-place on that coil (previous repair attempt possibly). I was told the same thing about the clips but that using shrink-tube was a serviceable option. I'm planning to replace the coil so I'll play with this one in the mean time.

 

[Hydro_Therapy]

Ok. Put new wires on both coils Friday- wasn't too bad, one coil had the clips:

The other just had the wires glued in with something cheap because they slid out fairly easy. I put the new wires in both coils and used a dab of dielectric grease to 'seal' them. Zip-ties to secure the wires in the coil without clips, re-used the clips on the other (pain in the ass getting them off the old wires but patience pays). As part of my diagnosis process, I swapped the coils side for side. Both engines fired right up and seemed to run well on the hose but I also leaned both engines just a tad due to really black plugs from my last run. We took the boat out yesterday for a test run, port engine ran fairly well (still need to get the low speed mixture and idle dialed in) but the starboard engine flat died while scooting along at about 1/2 throttle. After a bit of toying, we got her restarted and headed in- the weather was NOT conducive to any 'tuning' so we called it a day and I plan to replace the starb coil or both if I can find a source for new. We will tune up and test again soon but I think the coil was the cause of my issue, not totally confirmed as we didn't stop a while and try to restart, but the port engine that was giving us trouble before ran flawlessly, and the starboard engine that didn't have any issues before did give us some fits- that's why I swapped the coils and it seems to have been a good diagnostic tool. The wires probably contributed as the port side had standard graphite core while the starboard had copper- which is what I used for the replacement on both.

More soon I hope.