High hour 4tec’s

[Jaxtoce1]

Alright so, looking into potentially buying a 4 Tec. Currently have a 96 gtx 787 and a 2000 gtx 951 Carb’d... my reason for doing this is the skis I have now are now becoming so old there’s always some catastrophic problem every season. So now I look to 4 Tecs.. my question is, how reliable and how many hours could you put on a N/A 4 tec?/ and/or a supercharged 4 tec? The 4 tec skis I’m looking at would be like 2004-2007 so there really not THAT much newer than the ones I have now.. I know I saw a post like this before and I think someone said there GTI had like 400 hrs on it or something, can’t seem to find that now though.

Thanks in advance

 

[Dr Honda]

It depends on maintenance, and how it was used. Generally the N/A versions aren't beat as bad. The big problem is... guys don't watch the valve clearance, and one will drop. In turn... eating the engine. To me... at that point, it's not really worth the rebuild.

So... if you buy a 4-stroke ski of any kind... check the valve clearance. If they are getting tight... replace all the valves. That should buy you a lot of time.

 

[greenhornet2]

It depends on maintenance, and how it was used. Generally the N/A versions aren't beat as bad. The big problem is... guys don't watch the valve clearance, and one will drop. In turn... eating the engine. To me... at that point, it's not really worth the rebuild.

So... if you buy a 4-stroke ski of any kind... check the valve clearance. If they are getting tight... replace all the valves. That should buy you a lot of time.

Just curious here. Why would you replace the valves if the clearance is getting tight? Why not adjust the valve clearance? Coming from Automobile and Motorcycle background that is what we would usually do as long as not damage was done to the valves.

 

[Jaxtoce1]

It depends on maintenance, and how it was used. Generally the N/A versions aren't beat as bad. The big problem is... guys don't watch the valve clearance, and one will drop. In turn... eating the engine. To me... at that point, it's not really worth the rebuild.

So... if you buy a 4-stroke ski of any kind... check the valve clearance. If they are getting tight... replace all the valves. That should buy you a lot of time.

How involved would replacing the valves be? I’ve rebuilt my 787 twice now and am pretty mechanically inclined in the automotive/motorcycle world as well. Also how could I check the clearance ?

Thanks

 

[Arkie Bob]

I guess my 05 would be considered high hours, considering the total LACK of preventative maintenance. Oil and filter changes, spark plugs, have been pretty consistent. But the nose cone, wear ring, and SUPERCHARGER have never been touched in 250 hours! I bought it from the original purchaser who did everything himself, but he didn't know these areas required PM. I'm still using it, and will for another 4-6 weeks. But if it survives till cool water this winter will see all those areas serviced and rebuilt. (I'm a 46year career greasemonkey and own my own shop). This is the first I've heard of valve issues, what should I expect in that area?

 

[Jaxtoce1]

I guess my 05 would be considered high hours, considering the total LACK of preventative maintenance. Oil and filter changes, spark plugs, have been pretty consistent. But the nose cone, wear ring, and SUPERCHARGER have never been touched in 250 hours! I bought it from the original purchaser who did everything himself, but he didn't know these areas required PM. I'm still using it, and will for another 4-6 weeks. But if it survives till cool water this winter will see all those areas serviced and rebuilt. (I'm a 46year career greasemonkey and own my own shop). This is the first I've heard of valve issues, what should I expect in that area?

Wow 250 without a rebuild?? That’s crazy, I thought those were suppose to be changed every 2 years/100 hrs?

 

[Greg Moore]

Dropped valves have _nothing_ to do with clearance (which is done via hydraulic lifters) Dropped valves have to do with the heads snapping off the hallow sodium filled exhaust valves used in 04, 05 and early 06 SuperCharged only machines. It is catastrophic when it happens, they can be replaced as insurance or left to risk. A 155 with quality regular oil changes can last a really long time. The SC machines tend to get rode harder, are harder on engines anyway and often are run with ceramic washer shrapnel in the case.

 

[Chester]

There is no valve adjustment on Sea-Doo 4-strokes. Hydraulic lifters.

Chester

 

[greenhornet2]

There is no valve adjustment on Sea-Doo 4-strokes. Hydraulic lifters.

Chester

So what would cause them to get tight and why would you replace the valves?

 

[Greg Moore]

They do _not_ "get tight"
On just 04, 05 and early 06 Supercharged motors SeaDoo used hollow stemmed valves to reduce their weight for high RPM use. It was a really bad idea. If not perfectly stored (read fogged) every year, thin rust lines formed around the weld between the head the the stem (yes they're 2 piece friction welded). Once this happens then sooner or later the head breaks off, gets slammed between the piston and head a couple thousand times before the motor comes to a stop. Usual end result, piston shot, head shot, cylinder shot (which usually means upper block shot). In bad cases piston breaks, takes out rod and possibly crank. Essentially 1 single exhaust valve head and the entire motor is usually a write off.

If you have an 04/05 supercharged and for any reason you've had to pull the head, you'd be a complete idiot to not replace those exhaust valves while there. You can google what you're looking for, there is a super tiny number stamped on the tip of the valve stem visible with the cover off using a camera etc. One number series means you're good, other means you have the bad valves and are driving a time bomb.

 

[greenhornet2]

They do _not_ "get tight"
On just 04, 05 and early 06 Supercharged motors SeaDoo used hollow stemmed valves to reduce their weight for high RPM use. It was a really bad idea. If not perfectly stored (read fogged) every year, thin rust lines formed around the weld between the head the the stem (yes they're 2 piece friction welded). Once this happens then sooner or later the head breaks off, gets slammed between the piston and head a couple thousand times before the motor comes to a stop. Usual end result, piston shot, head shot, cylinder shot (which usually means upper block shot). In bad cases piston breaks, takes out rod and possibly crank. Essentially 1 single exhaust valve head and the entire motor is usually a write off.

If you have an 04/05 supercharged and for any reason you've had to pull the head, you'd be a complete idiot to not replace those exhaust valves while there. You can google what you're looking for, there is a super tiny number stamped on the tip of the valve stem visible with the cover off using a camera etc. One number series means you're good, other means you have the bad valves and are driving a time bomb.

Well that makes sense to me. I was more looking for Dr Honda's reason for this statement
"So... if you buy a 4-stroke ski of any kind... check the valve clearance. If they are getting tight... replace all the valves. That should buy you a lot of time." I just can't make sense of it.

 

[Greg Moore]

Maybe that's how Honda's work, he/she isn't Dr SeaDoo Mind you I've never seen _anything_ that required valve adjustment where they got tight over time, larger clearance yes and replacing wasn't the fix, shimming was.

 

[DavesNotHereMan]

I have a 2011 GTI LTD 155. I only use Amsoil and K&N filters. Oil changed every end of season.

I clicked 305 hrs today. Still hits 52 mph @ 6800 rpm. Did that today also. I put about 50 hrs a year on this ski. I use it every week. Original wear ring.

This is the Normally Aspirated, 1500cc (well, close), 155 hp (close again).

I am debating selling it, but (fingers crossed), there are no issues at all. Great ski.

Hope it helps.

 

[skiasylum]

Just a reminder that as stated the 155 is not supercharged and that there are different oil requirements per BRP for the supercharged models because of the friction washers in the supercharger.

 

[greenhornet2]

Maybe that's how Honda's work, he/she isn't Dr SeaDoo Mind you I've never seen _anything_ that required valve adjustment where they got tight over time, larger clearance yes and replacing wasn't the fix, shimming was.

I have seen atv's and motorcycles needing valve adjustment and they do get tight. never on a hydraulic set up though.

 

[mikidymac]

I have seen atv's and motorcycles needing valve adjustment and they do get tight. never on a hydraulic set up though.

You and everyone that works on engines. As anything with valve adjustments the wear parts are the valve and head. As the valves wear over time they work their way into the head from the valve or seat wearing and the valve clearance and cam or rocker decreases getting tighter requiring the adjustment to keep the spec clearance. Not necessary on hydraulic lifters though.

 

[ski&jeep]

I have an '04 S/C 155 with 280 hours, oil changed using Sea doo oil and filters every year, I just did the supercharger rebuild at the beginning of the summer and it had been done at least once before. This thing runs really good, 60 - 62 mph all day (or until I run out of gas). The PO installed a Solas impeller and ride plate a couple of years ago and I know the nose cone was serviced at that time. No issues so far for me.