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4tec SC guru's needed for trouble shoot

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GTX185

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Hello Folks- I own a 2004 Seadoo GTX SC- bought it new from dealer. It has 110 hours on it. Dealer maintained, always salt flushed and garaged after every use.. SC washers changed 10 hours ago... Never had a problem until recently... Was running WOT when it suddenly "bogged down" like the engine flooded and stalled out on me.. when trying to restart it would restart but idled very rough and would stall out... did this several times... after 30 minutes or so started right up like nothing happened... it ran absolutely perfect from then on for rest of day... about a week later I'm out on the ski... starts perfect.. runs perfect for an hour or so and when attempting to restart - starter engages but won't fire up... turns over like no tomorrow but won't fire up... I waited an hour or so and tried to restart - bam... fires right up and runs just perfect like nothing ever happened.... Get it home and change the plugs/... they looked fine but changed them anyway... Next weekend same exact thing happened.. starts up great - after an hour or it wouldn't restart again.. waited another hour or so and fires back up perfect...

Obviously an intermittent problem but not sure where to start troubleshooting.. I did not capture any codes.. forgot to check in my angst to get restarted.. that will be the first thing I do next time it won't start.. in the meantime any thoughts out there? Fuel pump? Electrical?

Thanks much,
Rob
 
Ok, engine is cutting out or will not run on restart when "Hot".:facepalm:
When hot, things expand. Start checking connectors and terminals. Start at the battery and clean the terminals. Disconnecting the battery is normally done by the mechanics when they work on the engine. Then keep checking down the line. Hopefully this does it.
 
Check around the SC where they would have been working. Make sure the connectors are intact and seated. Intermittent short when it gets hot and shut down, then engine cranks but no Engadget. Not the battery.
 
thank you for the replies. Let me clarify. The engine does not cut out... I turn the ski off myself throughout the day.. upon restart the ski tries to restart ie engine turns over... it just won't fire up like either its not getting enough fuel or proper spark. The battery seems just fine.. changed it last summer.. turns over fine and very strong. Stupidly I forgot to check for codes when it wouldn't start..

Its only doen this (not restarted) 2 times.... both times however it was like an hour or so before it would restart... both times once it restarted finally I drove it around and it ran perfect... when I would shut it down again and try and restart it fired right up again...

My thoughts were possibly a fuel pump starting to go bad?
 
GTX185 said:
thank you for the replies. Let me clarify. The engine does not cut out... I turn the ski off myself throughout the day.. upon restart the ski tries to restart ie engine turns over... it just won't fire up like either its not getting enough fuel or proper spark. The battery seems just fine.. changed it last summer.. turns over fine and very strong. Stupidly I forgot to check for codes when it wouldn't start..

Its only doen this (not restarted) 2 times.... both times however it was like an hour or so before it would restart... both times once it restarted finally I drove it around and it ran perfect... when I would shut it down again and try and restart it fired right up again...

My thoughts were possibly a fuel pump starting to go bad?
Click to expand...

Check for simple fixes first. Vapor lock can happen with cheap low octane fuels and/or low fuel pressure. Also try to move the throttle a little bit while starting. One more thing, throttle adjustment, should be little a quarters slack in the cable. How you down loaded any manuels free from Internet?
 
GTX185 said:
Hello Folks- Was running WOT when it suddenly "bogged down" like the engine flooded and stalled out on me.. when trying to restart it would restart but idled very rough and would stall out... did this several times... after 30 minutes or so started right up like nothing happened... it ran absolutely perfect from then on for rest of day... about a week later I'm out on the ski... starts perfect.. runs perfect for an hour or so and when attempting to restart - starter engages but won't fire up...
Click to expand...

Deja vu.
You just accurately described an episode I experienced last season on my RXT.
Change the plugs.
These units can eat plugs up, and the symptoms can be intermittantly dramatic to say the least...(and get you thinking hundred dollar bills in a heartbeat)
When they fail, its not always abrupt. They can get you chasing your tail with symptoms such as yours.
Spend the $10 or so for a fresh set and throw the old ones away. If thats turns out to be a no go, Matt and AC Doc are on it.

But I'm willing to bet $10 of yer money that solves it :thumbsup:
 
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door54 said:
Deja vu.
You just accurately described an episode I experienced last season on my RXT.
Change the plugs.
These units can eat plugs up, and the symptoms can be intermittantly dramatic to say the least...(and get you thinking hundred dollar bills in a heartbeat)
When they fail, its not always abrupt. They can get you chasing your tail with symptoms such as yours.
Spend the $10 or so for a fresh set and throw the old ones away. If thats turns out to be a no go, Matt and AC Doc are on it.

But I'm willing to bet $10 of yer money that solves it :thumbsup:
Click to expand...


Thanks D54- that was actually the first thing I did when I had the first symptom of an issue.. change the plugs.. unfortunately same issue is still with me... I read about some 4tecs having some very small holes in the exhaust manifold which is the cause of the engine probs.. when the holes first show up the issue is very intermittent. Since my ski is nearly 10 years old I'm thinking this might be plausible.. nonetheless I bought myself a couple of beers yesterday with my $10!
 
:cheers:

Rats...yep, there it is at the bottom of yer first paragraph..."change the plugs/". Flew right over that one.
My next lean would be of a preventative maintainence nature. You mentioned you salt flush after every use, but is it possible that one/some of your ground connections could have been compromised, leading to intermittent performance? That would be what I'd approach next.
 
Get a cold beer, park it under a shade tree (with a fan is nice), put the radio on and start checking all the connections starting with the battery terminals and engine ground terminals (which there are 3 that bolt directly to the engine directly behind the battery... helps to pull the battery out so it's out of the way). Use a small rotary tool with a round wire brush to clean each terminal and the place it bolts to so they're nice and shiney like new, apply a dab of synthetic marine grease to the surface and bolt them back together. You can't get to the hot cable connection to the starter without pulling the exhaust manifold out realistically, so I'd leave that till last and go test it 1st. While you're at it disconnect and reconnect all the plug connections, if you see any white powdery stuff anywhere then that cable is compromised and must be replaced! Any cable that is crunchy feeling when you bend it or has a white powder coming out the ends is corroded and must be replaced.

If during testing it does this again make sure to check for any error codes before pulling the lanyard, just in case it's trying to tell you something. Though this isn't really a SC issue, you realize at 100 hrs your SC is due a full rebuild replaced washers totally beside the point... it's time for new bearings and shaft and seals.

Good luck and "May the Force be with you!"

- Michael
 
well.. I checked all the basics and could find nothing wrong.. I went ahead and took it to a local PWC mechanic who I've known for a few years.. He told me the exhaust manifold had rusted through and water was getting up into the plugs. I flushed this thing religiously after every use with salt eliminator so a bit surprised something rusted thru.. It is 8 years old I guess... I am supposed to pick it up tomorrow.. anyone ever have an exhaust manifold issue?
 
The exhaust manifold is water injected, there will always be water in there when the engine is running... exhaust gases expel the water into the water box. The exhaust manifold is not double-walled or anything, raw water is sprayed into it directly to help cool and muffle the exhaust. If it's rusted thru, then water and exhaust gases would be getting out and into the hull (ie it would be leaking, but leaking into the hull).

That diagnosis does not make any sense to me.

If water gets into the cylinders it will hydrolock the engine it takes VERY little water to stop the engine since water does not compress. If only a tiny mist was getting into the cylinders (such as by a leaking intercooler... you sure he didn't mean the intercooler has rusted thru right?), it might not lock the engine but shouldn't bog the engine down as you described... plus moisture in the air-fuel mix should leave a residue on the spark plug tips if I'm not greatly mistaken (especially if we're talking salt-water burning inside the cylinders!).

If the intercooler is leaking then I'd say that may be your problem (and it would need replacement no matter what if it were leaking), but the exhaust manifold leaking does not make sense to me.

- Michael
 
Hey ask him to show you what he's talking about when you pick it up tomorrow, K? Is he fixing it for you or did he just diagnose it for you? Take and post pics!

- Michael
 
Michael- thanks for the tips and advice. Is there a chance the a rust thru could have occurred internally on the engine side of the exhaust manifold? I have not been getting any water in the hull whatsoever... although this issue just surfaced so not sure how much water would be coming in, especially if it was a small hole..
 
I just don't know... when you refer to the "exhaust manifold" that to me means the part that bolts onto the side of the engine up against the exhaust ports. But that's pretty substantial metal (ie. thick) it wouldn't corrode thru easily... and even if it did have some corrosion holes the exhaust gases would still be pushing the water out and away from the exhaust ports. I don't see how water could enter the cylinder's thru the exhaust ports while the engine is running.

Your issue seems more related to something heating up than anything else, and I do not know what that might be attributed to at this point. See what that guy can show you when you pick it up Thursday... maybe he just wasn't too clear on what he'd found when he spoke with you about it earlier. IDK. If it's a bad exhaust manifold (and he can show you why it's bad) then it is a simple part to replace and you can buy good used ones off Ebay all day long. I just cannot fathom what he meant by the exhaust manifold is corroded thru, nor why that would cause the symptoms you described in your original post.

ps. If you had a small water leak while the engine is running you would never notice it, the OEM water extraction system would keep the hull sucked pretty dry... it works whenever your engine is running, but it's low volume and if you were to spring a leak while tied to a dock your GTX may well sink before you realize what's happening.

- Michael
 
I have worked on 2 or 3 that the exhaust manifold water jacket brakes thur right at the J pipe. This will let water in to the cylinders when you shut it down. If it is running the exhaust pushes the water out.
 
Is the manifold water-jacketed, or just water-injected?

I remember holding mine in my hands before bolting it onto my engine and I didn't think it was jacketed (as far as I could tell), it appeared to be merely water-injected from the front. That was in 2010 when I bought my RXT with the engine in pieces already so it's been a few years since I last looked at a Rotax exhaust manifold from one of these machines.

I'm pretty certain the exhaust manifold does get water inside it by design, it has to and that's the reason why you have to be careful to have the engine running when flushing the intercooler and exhaust system out by waterhose.

- Michael
 
Your problem might be on the other side of the block, (ie intake side). If you have an intercooler (the 185 HP models do not) you may find that the salt has eaten a small hole in it. And when the engine is hot and then shut off, then attempting to start again your cylinders are getting a nice mix of water vapour/air/fuel causing your no start. When the engine cools down, all the water vapours just turn to water and sits in the bottom of your intake allowing your engine to start. I've experienced an issue like the symptoms your describing and the intercooler leak was the culprit.

Pretty simple to test, take the intake off, and shake it if you have water in there, pressure test the two cooling lines on the intercooler. I just put my hand over one of the water intake ports to block it and blow on the other one. Pretty simple way to see if intercooler is leaking.
 
Michael211_2000 said:
Is the manifold water-jacketed, or just water-injected?

I remember holding mine in my hands before bolting it onto my engine and I didn't think it was jacketed (as far as I could tell), it appeared to be merely water-injected from the front. That was in 2010 when I bought my RXT with the engine in pieces already so it's been a few years since I last looked at a Rotax exhaust manifold from one of these machines.

I'm pretty certain the exhaust manifold does get water inside it by design, it has to and that's the reason why you have to be careful to have the engine running when flushing the intercooler and exhaust system out by waterhose.

- Michael
Click to expand...
The manifold is water-jacketed. The water enters from the front large hose and exit the two small hoses by the Jpipe. Water never enters the manifold. You can test the manifold by blocking two of the holes and blowing thur the other if air exits it has a hole and is no good.
 
I picked up the ski yesterday. The exhaust manifold had a small hole that was apparently letting water back up into the motor.. Tech told me when the ski was shut off the water would vaporize and get up into the upper cylinders.. fouling the spark plugs and making it difficult to restart at times and or running rough. I got it home and put it on the lake and ran it hard for an hour or so.. ran like a champ and restarted on the money within a half a second all 25 times I restarted... hopefully this cures my ill... Thanks for the all the input and information.. I've done a lot of work on cars and motorcycles but am somewhat clueless on these 4-tec rotex motors.. btw- mine is supercharged 185HP.. no intercooler... Thanks again. Rob
 
Cool Rob! So glad you got it fixed and can now concentrate on enjoying the rest of this season! Thanks for coming back and posting the final resolution, who knows who all it might help in the future. Amazing that a tiny hole could cause so much grief. Can you tell us how much the replacement manifold set you back on this?

- Michael
 
Michael211_2000 said:
Cool Rob! So glad you got it fixed and can now concentrate on enjoying the rest of this season! Thanks for coming back and posting the final resolution, who knows who all it might help in the future. Amazing that a tiny hole could cause so much grief. Can you tell us how much the replacement manifold set you back on this?

- Michael
Click to expand...

I was wondering the same thing. Thanks
 
It was great to be back on the water... The ski ran perfect! I was given two options for the repair- one was to install a brand new exhaust manifold for $900. Second option was to go with a used part taken out of a blown motor for $500.. the used manifold was in very good cond... I went the used route... this is at a jet ski repair shop not affiliated with a dealer..
 
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