1998 GTX RFI Gremlins

[MontyP]

Hi All,

I have a 1998 GTX RFI which I really like. It has been a pretty reliable machine, fast enough for me and nice to ride. However, over the past couple of seasons I have experienced several "issues" which may or may not be related and am hoping somebody here may be able to offer some insights as to possible causes. The issues I have experienced are as follows:

1. The machine seems to chew through batteries. I purchased a brand new battery last year. It was charged but does not seem to hold the charge for more than 24 hours (i.e. I can install the fully charged battery, start the machine and run it for an hour - if I shut it off there is a good chance it will not start the next day without a boost).
2. When the machine first starts running it will hit 54 mph. After 5 or 10 minutes the top speed drops to 49 mph. It could be my imagination but the machine seems to run better when the air temperature is cooler.
3. When I took the machine out of storage this year and installed the battery (which had been kept on an "intelligent" trickle charger) it started right away. I ran it for 15 seconds to burn off the bit of oil I had sprayed in the cylinders and then shut it off. However it would not start again without a battery boost.

I have already replaced the rectifier twice and the impeller.

Any thoughts/suggestions would be appreciated.

Thanks in advance.

 

[Coastiejoe]

1). Have you tested the voltage at the battery when running? At idle and when revved up?
2). Very common to run better when the air temp is cooler. The air is more dense and the more air you can get into the cylinders the better performance.. This is why many buy and install cold air intakes.
3). Load test the battery,, You need know where the battery stands, load testing si the only way to KNOW..

 

[DavesNotHereMan]

Hi All,

I have a 1998 GTX RFI which I really like. It has been a pretty reliable machine, fast enough for me and nice to ride. However, over the past couple of seasons I have experienced several "issues" which may or may not be related and am hoping somebody here may be able to offer some insights as to possible causes. The issues I have experienced are as follows:

1. The machine seems to chew through batteries. I purchased a brand new battery last year. It was charged but does not seem to hold the charge for more than 24 hours (i.e. I can install the fully charged battery, start the machine and run it for an hour - if I shut it off there is a good chance it will not start the next day without a boost).
2. When the machine first starts running it will hit 54 mph. After 5 or 10 minutes the top speed drops to 49 mph. It could be my imagination but the machine seems to run better when the air temperature is cooler.
3. When I took the machine out of storage this year and installed the battery (which had been kept on an "intelligent" trickle charger) it started right away. I ran it for 15 seconds to burn off the bit of oil I had sprayed in the cylinders and then shut it off. However it would not start again without a battery boost.

I have already replaced the rectifier twice and the impeller.

Any thoughts/suggestions would be appreciated.

Thanks in advance.

1. My 2001 GTX RFI does not seem to have that problem. I am on my 3rd season with a Duralast Gold battery. It was also "intelligently" trickle charged. This weekend, started up after a 3 week sit and got a 12v Low, but 10 minutes of riding and it was topped off. My guess is that 2 years is all you are going to get out of a battery. I'll bet mine goes south before the season ends. As [MENTION=43374]Coastiejoe[/MENTION] says, check the charging voltage when running.
2. Not only Temp, but Humidity and air pressure. Temp, the air pressure and humidity create a new "Temperature Altitude" that can affect performance. Aircraft Pilots (especially General Aviation) have to use this all the time.
3. +1 on the load test. It may have enough juice to run, but not to crank. Load test the battery (AutoZone will do this)

-Dave

 

[MontyP]

Thank you very much Coastiejoe and Davesnothereman. I appreciate the prompt responses. I will load test the battery (or at least get a friend who knows how to do so ) the next time I get up to the cottage.

I understand the point re the air temperature's impact on performance. However, the last few times I have ridden the machine it starts off running fine and doing 54 mph but then slows down to sub 50 mph within a few minutes of running. This is not due to a change in air temperature (as it happens over a very short period) but seems to happen when the machine itself warms up. Any thoughts in this regard?

Thanks again.

 

[MontyP]

Also, do you think the drop in top speed after a few minutes of operation could have anything to do with the battery issue or are the two most likely to be unrelated?

 

[DavesNotHereMan]

Also, do you think the drop in top speed after a few minutes of operation could have anything to do with the battery issue or are the two most likely to be unrelated?

There is an old but very helpful thread on here called the RFI spot. I don't have the link, but search for it. Read through all of it.

If I remember correctly, the RFI's take a huge pull of juice to run at the top, so the battery could be the culprit.

I know you said you changed the rectifier, are you running the 4 -tech from OSD or aftermarket replacements? Somehow, I just have a suspicion that AC is leaking past there and that is eating up your batteries.

But, I could easily be wrong and hopefully one of the RFI experts on the forum will answer.

- Dave

 

[Coastiejoe]

Some skis MUST have great voltage/amperage for the true performance to be there. In many cases, if the battery gets to 10.8 volts or lower it will no longer power the MPEM...

So yes, voltage could be the issue. However, until you have a KNOW good or bad battery, you are kind of wasting your time. KNOW items are priceless, know bad is just as good, and often better, than known good,,,

 

[MontyP]

Thanks again Coastiejoe and Davesnothereman. I bought the rectifiers from a SeaDoo dealer but do not know if it is aftermarket (I assume not).

I am not very mechanically inclined so will get a friend to help me diagnose. Dave - when you said "Somehow, I just have a suspicion that AC is leaking past there and that is eating up your batteries." do you mean you think there may be an issue with the rectifier itself (which was replaced the year before last) or would something else cause "AC to leak"? If the rectifier might need replacing again is there a specific type you would recommend? What about batteries - I have a Yuma at present - do you think there are better batteries for the SeaDoo?

Thanks again gents.

 

[Coastiejoe]

One of the ways the rectifier fails is to allow A/C to get to the MPEM. When that happens, it screws with the skis performance. In most cases it will still charge the battery. So,,, the test is to unplug the rectifier and see if the glitch goes away.

In your case, we need to KNOW you have a good battery and what the charging voltage is before we do the unplug test.

Gets VERY challenging to diagnose things if we start jumping around.

 

[MontyP]

Understood. I will check the battery when I am next at the cottage (probably not for a few weeks).

 

[DavesNotHereMan]

As far as batteries, I assume you mean Yuasa, there is nothing wrong with that brand. That said, you must work from a KNOWN starting point. That is why [MENTION=43374]Coastiejoe[/MENTION] is recommending the test. It doesn't matter which brand battery you have if it won't hold a charge or keep it under load.

 

[mikidymac]

Do not BOOST any seadoo, especially injected ones as you can fry the electronics.