What is a safe cruising RPM - 2005 GTX 4-Tec Non sc

[boatrboy]

I am new to the GTX and it seem to run great with around 200 hours on it. It is not supercharged.
I don't want to push it so I am wondering what is a safe cruising rpm for this motor?

On my boat most recommend 75% of wot. I can't seem to find anything documented for this ski so I thought I would reach out to the experts.

Yesterday I cruised for a couple of hours and most of the time it was around 35 mph and IIRC it was around 5,000 rpm (maybe a little more- can't remember exactly). I do realize this won't be a 60 mph ski like my old RX and I believe max rpm is 7300.

I put around 20-30 hours per year and want this to last a bit so I worry running at at 6,000 rpm most of the day may put a lot of undue stress on this motor.

What are your thoughts?

Thanks

 

[boatrboy]

Any 4-tec experts out there?

 

[benjilafouine]

The rule of 75% seems to be a good practice. A friend of mine was even talking about it yesterday.

 

[Rikky001]

Don't want to spoil it but better buy a kayak if you have to worry about "safe" cruising speed. The only deciding factor will be yourself how long you can hang on the PWC.

Keep your PWC maintained as per manual, warm her up before you go mad, flush her after each ride - and just enjoy the ride.

I don't claim to be a 4tec expert, just take care of > 30 PWC's and yachts professionaly. Only PWC's driven on the ocean so I see mostly broken engine mounts as root cause of all problems. Spectacular jumps comes at a hefty price. All the PWC's are driven hard for extensive periods of time, most of them supercharged, and very little issues (2010-2018 models). Only difference is that these PWC's are taken care of. WOT no influence, supercharged or not. The engines are designed to go WOT as long you can hang on.

After a day at sea we always check engine mounts - and replace before they fail. We do engine alignment as standard spring check; this is a crucial thing and in lot of cases "forgotten". Electronics, sometimes thing just stop working but in general very little issues. (stators seem to fail more often but not a real big deal to lift the engine and replace the stator and seal of the water pump plus alignment when you have the proper special tools)

Newcomers mostly buy a new or cheap PWC, try to keep up with the die hards and the fun stops usually between 1 hour or few hours leading to disappointments and funny comments on forums.
Don't expect a cheap ski you bought somewhere without having any clue to be in a good condition, mostly it is in a crap condition and this ends in questions about WOT or not. It is not nice driving a ticking money pit squeezing your ass cheeks tight when driving WOT and thinking will it fail or not.
Driving at 75% WOT might ease your pain in your mind but only in your mind.

My advice, if your PWC condition is unknown, get it up to standard. If you don't have money to go to a dealer, do it yourself, if you can't do it yourself expect hefty costs one day, usually when you are far out with a n empty phone battery Alternative is buying a kayak or a peddle board.

 

[benjilafouine]

WOT is like flooring your car, leaving some rubber on the asphalt and hard braking all the time so if you don't mind, I'll stick with that 70% rule along with old plain good sense. I am convinced that a beaten ski will last less longer. And P.S.: I have a 2018 ski and my 2003 GTI LE has 215 hours on it.

Of course, if you can check up on them every day and do 100% of all the maintenance immediately by yourself, this is great, but some (if not most) of us do not do that for a living. I do check them every day and at the first sign of an issue I act on them immediately but I avoid doing stupid things such as running at WOT all the time, spending my time jumping waves, beaching my ski and flipping it over.

But I agree with the kayak thing... Much less expensive!

 

[Rikky001]

Forget to mention "don't take it personal", sorry for that.
Up to you my friend if you are happy with 70% that is all what is needed.

 

[boatrboy]

Rikky- I too do not know how to take your post. While I understand you don't know me or my capabilities, your post suggested I was some kind of an idiot the way I read it. I don't recall ever saying I bought a cheap ski or try to keep up with the stunt Devils. I don't work on these for a living but have a tremendous amount of experience in the motor world and my question has merit.
I guess I appreciate the lengthy post, and maybe it just sounded rough but I will look forward to reply from folks who have experience with non sc 4-tecs.

 

[mkov608]

Drive it like you stole it! Been doing that (along with all the recommended maintenance) for years now. Only issues on my 2002's seem to be electronic ... replaced both information centers due to water intrusion, one MPEM due to a faulty MB connector, 2 J-pipes (same ski) due to exhaust leaks, one camshaft sensor, two hood lift struts, and the occasional wear ring. The engines seem to be bullet proof! Run WOT all the time, and for long runs when the ocean is calm! You get tired quickly going WOT on rough water.

There's nothing in the owner's manual about running 75% of WOT (how would you measure that anyway?) The relationship between throttle percentage and speed is not linear especially in a turn. Besides, the I'll bet the engineers at Rotax did their homework and there is a safety factor built into the set max RPM (ECU controlled) and when the engine would experience a catistrophic failure due to prolonged high RPM operation.

If Sea-Doo did say to limit your throttle fun factor, I bet they'd lose a lot of customers to Yamaha. Can you imaging a sales pitch like:

Try out the all new Sea-Doo GTX 300, but we recommend you only use 225 horsepower because our engines are shoddy and will fly apart with prolonged operation at high engine RPM.

 

[boatrboy]

Drive it like you stole it! Been doing that (along with all the recommended maintenance) for years now. Only issues on my 2002's seem to be electronic ... replaced both information centers due to water intrusion, one MPEM due to a faulty MB connector, 2 J-pipes (same ski) due to exhaust leaks, one camshaft sensor, two hood lift struts, and the occasional wear ring. The engines seem to be bullet proof! Run WOT all the time, and for long runs when the ocean is calm! You get tired quickly going WOT on rough water.

There's nothing in the owner's manual about running 75% of WOT (how would you measure that anyway?) The relationship between throttle percentage and speed is not linear especially in a turn. Besides, the I'll bet the engineers at Rotax did their homework and there is a safety factor built into the set max RPM (ECU controlled) and when the engine would experience a catistrophic failure due to prolonged high RPM operation.

If Sea-Doo did say to limit your throttle fun factor, I bet they'd lose a lot of customers to Yamaha. Can you imaging a sales pitch like:

Try out the all new Sea-Doo GTX 300, but we recommend you only use 225 horsepower because our engines are shoddy and will fly apart with prolonged operation at high engine RPM.

Thanks for the reply - how many hours are you seeing on your 4-tecs?
Btw in reality I am sure they won't advertise as you suggested but I don't remember in my RX manual Seadoo stating " Our 2 stroke versions need to be rebuilt every 200" which for some guys here would be every 2 years .....

 

[mkov608]

Both of my '02s have 150 hours on them.

You "don't" remember? I had a '95 XP with the old 720 2-stroke engine. Rode/maintained it the same way, and I never had an engine problem. Sold it when I moved overseas.

There was no hour meter on the old XP, and there was nothing in the manual about rebuilding the engine. What year was your RX? I'd like to look that up. Reciprocating airplane engines get rebuilt after a designated number our hours, but Sea-Doos? Sea-Doos don't tend to fall out of the ski when the engine fails.

 

[benjilafouine]

My 2003 is going strong at 215 hours on the new engine. The owner before me sold it to me at 90 hours and it broke at 130 I believe due to a botched job to repair a hole in the muffler using some JB weld. That makes the rest of the ski 345 hours and it still looks new.

I took my ski out of the water last week, checked the hours with the CanDoo, checked compression (145 psi in both cylinders), checked carbon seal (A1), plugs, etc. There was nothing to fix! Returned it in the water for some more fun although I always go easy on my skis.

 

[boatrboy]

Mkov. I just just being sarcastic since almost every forum has folks stating the 2-strokes need rebuilding every 200 hours or so. This was the case for me as I bought my 2000 RX from a friend who blew the motor at around 220 hrs. I had to pull it and decided on having SES rebuild it rather than doing this one myself. I sold it after a few years to get this GTX as I wanted a better ride. I'm not a kid anymore.

 

[benjilafouine]

It's kind of funny: when I put my GTI on eco mode, it gives me approximately 75% of the power...

 

[boatrboy]

It's kind of funny: when I put my GTI on eco mode, it gives me approximately 75% of the power...

See - I may be onto something