Idle Adjustment on 98 GTX RFI

[gecko4456]

My 98 GTX RFI (bought at auction and havn't had it in the water yet) starts easily and seems to run fine, but doesn't want to idle at all. I have no idea what adjustments there are that I can make and what's controlled electronically. Hopefully someone here can help me out. It has new plugs (BR8ES). The gas in it may be partly the problem. I have no idea how long it sat before I bought it. I will drain it this weekend and replace with fresh gas to make sure that's not partially the problem. Last weekend I started it up and the langer I had it running the better it seemed to get. How long should it take to warm it up enough to idle? What should the idle be at out of the water anyway? Any help would be much appreciated.

Thanks
Sean

[Technical Support]

Bad gas can certainly do it, and you do need to rule that out before going further. Idle is usually around 1800 out of the water on an RFI I believe. There is nothing you can self adjust. It should start and idle within 2-3 start attempts.

[ April 16, 2003, 09:48 AM: Message edited by: Technical Support ]

[gecko4456]

I put new gas in and it's definitely better, but still doesn't idle. It tries to idle at about 800-900 RPM, running fairly roughly and eventually stalls. The engine seems to run very well at higher RPMs. If I throttle it to about 2000 RPM or so it runs great. It's very easy to get started, but I decided to try it out in the water this weekend and it will not start in the water. The engine turns over fine, but it just won't go. I put it back on the trailer and it starts right up, put it back in the water and it won't start. I tried starting it on and off the trailer several times with the same results. Finally I started it on the trailer in neutral with the edge of my glove wedged in the throttle so it was around 1900. I then put it in the water real quick before overheating and it ran fine in the water. I didn't dare ride it though for fear that if I stalled I wouldn't be able to get it started again. So I guess I have two questions here. What to do about the idle and why won't it start in the water. And before anyone tells me to take it to the dealer I should let everyone know that I live on an island without a Bombardier dealer and it's quite an expense to ship it. Any suggestions would be greatly appreciated. Thanks again for any help.

[Technical Support]

There's nothing you can do - you need to take it to a dealer. The sensors need the Dealer computer for diagnosis and adjustment.

[gecko4456]

Well, it gets even worse. I took the new spark plugs out just out of curiosity and one had carbon deposits like a normal plug would. The other one had nothing - just a little unburnt fuel maybe. My guess is I'm running on one cylinder. I can't believe it runs this well on one cylinder, but that's what I'm guessing. I borrowed a compression tester and the good cylinder reads 150psi. The other reads 125psi. I was in a hurry when I tested it, so I need to recheck it and make sure, but I'm pretty sure my idle problem isn't due to faulty electronics at this point. What's my next step?

[Technical Support]

If that compression reading is right, that engine is shot. An RFI won't even run to plane out on 125 psi, so I wouldn't be surprised if you are running on one cylinder.

[gecko4456]

So what's my next step? Pull off the head and have a look? What might be the cause? could it just be a broken ring? What am I most likely looking at - new pistons and reboring the sleeves?

[Technical Support]

Yes you can pull the head and look - most likely you will find some damage. You need at least a top-end job.

[gecko4456]

Well I took it apart today and guess what? One of my pistons matches the picture you have posted from an engine that suffered water ingestion. The other has slight damage but not as bad.....yet. Also, the crankcase is full of water. The crankshaft and rods seem fine, but I can't belive the engine ran at all after seeing the pistons. So now I have several questions.

1. How does that much water get into the crankcase and how does it do that kind of damage to the pistons?

2. How do I prevent this from happening again?

3. There doesn't seem to be water in my oil or in any of the oil lines even though the crankcase is full of water. Why?

4. How does the oil flow through the crankcase anyway? Is it just gravity fed? I am just having a hard time believing my oil isn't contaminated with water and that there wasn't more oil in the case.

5. What pistons should I order and what specs should I tell the machine shop to bore the sleeves out to?

6. Do the sleeves separate from the water jackets and if so how? I wasn't sure and didn't want to mess anything up worse.

Wow, I know this is a lot of questions. Thanks in advance. You guys rock!

[Technical Support]

You need a full rebuild, forget the top-end idea. Your crank bearings are shot if left in water like that.

The center section is the only part in oil, and it's sealed.

Water can get in from sucking it throught he thorttle bodies, from the exhaust is turned over the wrong way, from being towed too fast in the water, from flushing incorrectly, from a cracked exhaust manifold, from a leaking head, etc.

You need to inspect everything to make sure you don't have a problem, but without the full first person history you will never be 100% sure of what happened.

[gecko4456]

So there shouldn't be anything in the crankcase at all? No water or oil? What makes the oil circulate through whatever sealed part it circulates through? Is there an oil pump? I still have a hard time believing the crankshaft bearings are shot. There's no rust or anything. Everything feels great to me.

[Technical Support]

No there should be no water in the case anywhere.

The oil is slowly circulated just from the gear mesh pushing it through.

[Bill O'Neal]

No need to pull the sleeves from the clyinder castings, they bore them with them installed into the castings.

You have a two stroke motor. No oil should be in the parts of the cases where the crankshaft throws are, only in a seperate chmber for the counterbalancer. Oil is injected into the flow of fuel going through the motor and is burned with the combustion in the chambers of the head and pushed out of the exhaust pipe.

If the water was left inside of the motor crankcases for more than a few hours, you crankshaft and rod and wristpin bearings will have formed rust pits. These pits will create excessive heat in the bearings and you will lose a bearing sooner or later. Buy a remanufactored motor from SBT and replace the whole long block. You will be money ahead in the long run. You have no way of telling the condition of your crankshaft and rod bearings by looking or feeling them.

[gecko4456]

Thanks. So should there be no oil in the case either ? Or should it be full of oil? Also, do the sleeves separate from the cooling jackets or should I just take the whole thing to the machine shop as one piece?

[gecko4456]

I have no doubt you're right, but I have very limited funds right now and really want to get this baby running even if only for a short time (hopefully not a REALLY short time). I'm going to take my chances and do the top end only and hope for the best. I don't see any rust at all and like I said everything feels great. Worst case is I'll be back for an entire engine next time around. What size pistons are available for my engine and what size will I need to have the sleeves bored out to?