Long intro to Timing Chain fix

[RowdyRod]

G'Day from Downunder,

This is a little thread on my journey to fix my Speedster 150 (155HP non supercharged)

When I brought the boat last year it had 97 hours on the clock and an unknown “electrical” issue... I ended up having to pull the engine out and replace a broken stator... that involved a whole lot of new learning, swearing, breaking bolts, more swearing, bruises, even more swearing... I'm sure you know how that is.... eventually after replacing the stator, new engine mounts, new drive shaft, new TOPS and a bunch of other little things, my Speedster was up and running well. Since that fix I have added over 33 hours of fun filled happy jet boating. A lot of thanks goes to all the people who have provided advise on this forum both directly and indirectly.

Easter was going to be our last big family holiday for the summer season and we headed away for 4 days of skiing and kneeboarding, it was perfect weather, glassy water, mild temperature, clear blue skies.... I should have known something was up!

After about an hour and a half of racing my cousin in her Regal Rush XP (120 HP 2 Stroke Mercury) we headed back to the dock. Top end speed on both the boats were similar, but the handling and acceleration of the SeaDoo was far superior, and the SeaDoo just looks better... (and smells better) I should not have bragged about it so much...



As we were idling back to the dock at less that 3 knots the motor just stopped dead. At the time I did not know it was the timing chain and tried several times to re-start before giving up and paddling back to shore. When I finally got the boat home, after 4 days of beautiful weather AND A DEAD BOAT, I removed the camshaft cover and the missing chain was obvious and I could also see 2 broken exhaust rockers.

Time to pull the engine again



More progress reports to come...

 

[Eclipse1701d]

It is a great looking boat! Hang in there, from the sound of it, you will persevere!

 

[JPass]

Wow that sux. Post some pics of the damage, but I'm assuming you have some damaged valves in addition to the broken rockers. Hopefully no piston damage and that the head is salvageable. What's with the rust on the rocker shaft?

 

[Sportster-2001-951C-Stock]

Good, Bad, Ugly!

Indeed.

Is your chain stamped "ROLON" by any chance? An "IWIS" chain is the solution I'd bet, get their best one and I think it's the LS (long Service). A good vender will know which one, it makes a difference.

The motors in these pics ate "ROLON" stamped chains.

FWIW, LINK-BELT is the old design that's been around forever and lives 30 years but not likely an option in the case of 4-TEC.....

 

[RowdyRod]

Wow that sux. Post some pics of the damage, but I'm assuming you have some damaged valves in addition to the broken rockers. Hopefully no piston damage and that the head is salvageable. What's with the rust on the rocker shaft?

Pistons look good apart from some carbon build up... it looks like the engine was running pretty rich at some stage. I did not have the tools to check the valves, so the head is at the shop waiting on inspection... from the outside they look fine, but time will tell. There is surface rust on the rocker shaft and pretty heavy rust on the timing gear and thrust washer, everything else was pretty clean. The TOPS valve was broken when I got the boat so I suspect it had got some moisture in there during storage.

 

[pete63]

G'Day from Downunder,

This is a little thread on my journey to fix my Speedster 150 (155HP non supercharged)

When I brought the boat last year it had 97 hours on the clock and an unknown “electrical” issue... I ended up having to pull the engine out and replace a broken stator... that involved a whole lot of new learning, swearing, breaking bolts, more swearing, bruises, even more swearing... I'm sure you know how that is.... eventually after replacing the stator, new engine mounts, new drive shaft, new TOPS and a bunch of other little things, my Speedster was up and running well. Since that fix I have added over 33 hours of fun filled happy jet boating. A lot of thanks goes to all the people who have provided advise on this forum both directly and indirectly.

Easter was going to be our last big family holiday for the summer season and we headed away for 4 days of skiing and kneeboarding, it was perfect weather, glassy water, mild temperature, clear blue skies.... I should have known something was up!

After about an hour and a half of racing my cousin in her Regal Rush XP (120 HP 2 Stroke Mercury) we headed back to the dock. Top end speed on both the boats were similar, but the handling and acceleration of the SeaDoo was far superior, and the SeaDoo just looks better... (and smells better) I should not have bragged about it so much...

View attachment 35059

As we were idling back to the dock at less that 3 knots the motor just stopped dead. At the time I did not know it was the timing chain and tried several times to re-start before giving up and paddling back to shore. When I finally got the boat home, after 4 days of beautiful weather AND A DEAD BOAT, I removed the camshaft cover and the missing chain was obvious and I could also see 2 broken exhaust rockers.

Time to pull the engine again

View attachment 35060

More progress reports to come...

all the best mate!!!
i havent really heard of many chains going.....learn something new ever day!?
where are you located?

 

[RowdyRod]

Is your chain stamped "ROLON" by any chance?...

I did not think the chain had any markings... but you made me take a much closer inspection and it looks like it's stamped with JW or JWS on some of the links.



EDIT - Ok, so I did a bit of research and it seems that I had a JWIS chain which is the same as the IWIS ones.

 

[RowdyRod]

Thanks mate, I'm from Melbourne, Bentleigh.

 

[RowdyRod]

More pictures...

Engine out and on stand.... still attached to crane as I did not trust my cheap stand... turns out I need not worry as it holds the engine well.


Chain did very little damage to block.


A large tent peg is a perfect crank shaft lock

 

[RowdyRod]

More parts off than on....

I need to re arrange my parts storage


Here are the two broken exhaust rockers...


The head


And the block...

 

[Sportster-2001-951C-Stock]

Okay, I don't see any damage to piston or valves, the weak valves with fragile stems can be found by checking the stamped number on the stem just above the keeper inserts. Those stems were hollow sodium filled, eventually would break and drop a valve head. Makes a royal mess......

 

[JPass]

Surprisingly little damage. Curious if those are the dreaded Na filled stems like Sportster assumes. My guess is yes due to the fact that nothing else broke. Keep us posted on the repairs.

 

[RowdyRod]

Thanks guys... I think the low damage is due to being at low rpm with a nice warm well lubed engine and a lotta luck

Originally I was going to take the engine to a repair shop about 40km away from me, I had dealings with them before and they seemed OK, but they were quoting somewhere between $3800 and $4000 AUD to do the repairs, then I started to think I would be better to do a core swap with the SBT outlet we have here in Australia but that was going to cost me $4200 AUD including freight costs... and who knows what sort of block I would have ended up with.

With these crazy costs I figured I would at least try and strip the engine down myself and assess the damage. That's when I got onto a guy who is much closer to me who has given me the confidence to do the build myself with him doing the bit's I can't like, honing cylinders and decking the head. It will still cost me a lot of $$$ in parts, but at least I know exactly what is being replaced and why.

 

[Sportster-2001-951C-Stock]

I'm not sure I'd be in a hurry to go through an entire rebuild, my guess the head is plenty flat and if those valves are the later ones they should be fine too, now's a good chance to throw good ones in if they're the weak ones though.

Although I don't completely disagree with your approach, using a new chain and rockers might've diagnosed compression before pulling it all apart, that would tell you about if a valve was bent/leaking or maybe (big maybe) upper ring land has been pinched.

I wish I knew the mysteries of those chains a little better so I could contribute wisdom, sorry. My feeling is it was damaged during the high speed run and yes, you were quite lucky it broke afterward as opposed to when things were flying around high speed.

The broken rockers raise concerns about pistons kissing valves but it looks like that didn't happen? I do see some engines that aren't run enough or run using gummy/trashy fuel the valves can hang up and stick in the guides slightly then push rods fall out of place this leads to broken rockers and bent push rods. Sometimes the cam and lifters are damaged from the excess force.

Speaking of luck, all that needs to happen is a valve spring break or valve keeper pops lose and whammo to a motor that was otherwise in excellent shape! So yeah, I was expecting to see bent valves and matching divots in those pistons, minimum.

 

[RowdyRod]

Thanks for the input guys! just a quick update....

I got the head and block back from the machine shop over the weekend, looks nice and shiny now after it's ultrasonic bath

The intake valves were the old ones with the serial number starting with 72 the exhaust ones started with 75. I decided to have them all replaced with some quality valves. Also had the cylinders honed, new rings, surface grinds, crankshaft linish and new bearings.

It's back on my stand now and ready for reassembly....