Oil hydro-locking twin 717

[LM53]

I have a 2000 14.5 challenger with twin 717. When I went to start the engines for the first time this season the right engine started fine but probably ran 2 quarts of oil out of the exhaust (clean two-stroke oil). The left engine would just hydro-lock wouldn't even turn over. I pulled the plugs out and it turned over fine but blew lot of clean two-stroke oil out and after reinstalling the plugs the engine started fine but like the right engine ran a lot of oil out of the exhaust. My question is are the pumps bad or are there check valves somewhere that are stuck open. How would two-stroke oil find its way into the engine while in storage.

 

[Coastiejoe]

I have a 2000 14.5 challenger with twin 717. When I went to start the engines for the first time this season the right engine started fine but probably ran 2 quarts of oil out of the exhaust (clean two-stroke oil). The left engine would just hydro-lock wouldn't even turn over. I pulled the plugs out and it turned over fine but blew lot of clean two-stroke oil out and after reinstalling the plugs the engine started fine but like the right engine ran a lot of oil out of the exhaust. My question is are the pumps bad or are there check valves somewhere that are stuck open. How would two-stroke oil find its way into the engine while in storage.

Your crank seals are weak/bad. Not worth fixing in most cases as it requires a new crank in most cases. During long storage the oil seeps past the seal and into the engine. When you crank the engine, you suck the oil right into the cylinders.'

Simply instal shut-off valves on the supply line from the oil tanks and shut the valve off during storage.

 

[Waterluvr]

Probably 75% of all the original Rotax 2 stroke engines that come in anymore I work on have leaking inner crank seals, even the low hour machines in the 150 or less bracket. My biggest concern is the mess they make dumping all that extra oil in the water when they are launched and started.

That's your heads up a rebuild is needed off season but this has been a pretty economical solution to keep old smoky from being a miniaturized version of the Exxon Valdez until the engine can be overhauled.

I'm adding these 12 volt 1/2" valves to the rotary shaft supply lines, just wire them hot and grab a ground off the return path of the DESS post and you never have to worry about remembering to turn a manual valve on and off it does it automatically from the lanyard being put on and taken off.

 

[racerxxx]

I will say what I find funny about all the crank seals leaking is all my Skidoo liquid cooled sleds never have this. They run the exact same crank seals and the skis, the cases are very close to the same as well. And those engines are from the late 70's to the mid to late 80's

 

[Coastiejoe]

That is interesting. I wonder what the running temp is of the jet ski vs the liquid cooled engines.


Sent from my iPhone using Tapatalk

 

[racerxxx]

I believe they run in the 175F range.

 

[LM53]

Probably 75% of all the original Rotax 2 stroke engines that come in anymore I work on have leaking inner crank seals, even the low hour machines in the 150 or less bracket. My biggest concern is the mess they make dumping all that extra oil in the water when they are launched and started.

That's your heads up a rebuild is needed off season but this has been a pretty economical solution to keep old smoky from being a miniaturized version of the Exxon Valdez until the engine can be overhauled.

I'm adding these 12 volt 1/2" valves to the rotary shaft supply lines, just wire them hot and grab a ground off the return path of the DESS post and you never have to worry about remembering to turn a manual valve on and off it does it automatically from the lanyard being put on and taken off.

thanks for everyone's help where is the best place to get a valve like this.

 

[LM53]

No need to respond on where to get a valve like that I have one coming off eBay for $13. The specs on the valve say it is for water and other low viscosity fluids. Have you had these valves on boats for a long period of Time do they hold up well.

 

[Coastiejoe]

The one concern I would have using a solenoid based valve is, if it it a wire fails, you will lose your engine.

I am conflicted. I like that you would not need to remember to turn the valve on, but hate that if it fails, the 15 dollar valve will cost you many hundreds of dollars.

 

[Waterluvr]

No need to respond on where to get a valve like that I have one coming off eBay for $13. The specs on the valve say it is for water and other low viscosity fluids. Have you had these valves on boats for a long period of Time do they hold up well.

Long periods of time? No Sir, it's a very temporary fix for an engine that needs to be rebuilt and the intent in my shop is that it lasts the duration of a boating season and prevents excess oil getting puked out into the water every weekend come time to start them up. You'll never get someone's teenager's to remember to turn on a ball valve that's out of sight before they grab the spare key and take off in a boat or ski or turn them off when they are done which is why I use them.

I tried the "hang the DESS key" on the ball valve routine, that just didn't work out for most of them. If it's a single responsible adult that's the only one ever at the helm of the boat or ski ball valves work just fine, for the rest of the world they end up smoking the crank driven brass gear on the rotary shaft in the first 1-5 hours of use when they don't get turned back on.

I install them free of charge to service customer's with the understanding the engine requires an overhaul, if they choose to ignore that I won't touch the ski or boat again the following season (or ever) until they choose to fix it properly at some point over the next 8-9 months while they sit unused in the off season.

I have reused the valves a few times over on some boats and ski's after they are fixed, haven't had a malfunction in one yet. The valves I install might see 10-15 hours actual use in any given season, ten years of use for what I do with them probably won't see as many on/off cycles as a 90 day period of time in most liquid applications they are used in.

I tested them for flow from the oil tank initially using synthetic XPS-II with a short length of hose below the valve into a catch container and when the valve opens it runs right through so there's no real concern for volume moving through it at all so long as the tank is 1/3 full or more they work really well.

 

[Coastiejoe]

Anytime a kid grabs a lanyard there is a gamble.. LOL
Like I said, I really do like the theory. If it was just me using my ski, I would do the ball valve. But if it was a ski others used, I would do the solenoid for sure. But,,, once you turn it on in the morning, you should need need to touch it again. If it leaks THAT bad, then the ski is in immediate need of repair.

 

[Seadoodoc]

Valve is a great idea! The boats all evetually leak on seals. Its not some bad seals as physics. The boat tanks are twice as high vs pwc . Pressure on the case seals are double intended watercraft design ( on a full) . very simple winterization trick I did for customers was empty oil tank for long storage.

 

[Raymond 88]

Anyone know off -hand what size hose it is that runs from the oil tank to the engine? I have the same problem with my 1999 787 GSX RFI after storage this spring. I pulled the plugs and tried cranking the engine to get most of the oil out on rags. After I re-installed the plugs the starter still wont turn over the engine except for a 2-3 second burst. Then just an umph sound. Any suggestions on getting this going to start the summer out?
Thanks

 

[Shaw520]

Ok ,.. bringing back a not so old thread here,.... but its seems these inner crank seal issues are even more common on the 99-01 RFI's, (why is that?)..
This solenoid idea is great but there IS that what if factor of a switch/wire failure = toasted engine,
..... be cool if they made this solenoid in reverse, so that it held the valve 'shut' while stored, (safer while running).. but I imagine that would draw too much from the battery in a short while. Maybe a Vacuum operated valve ?