1996 Sport Jet 120 water in Cylinder

[hkydan]

I have a 1996 SportJet 120 with water in the bottom cylinder. I have changed the exhaust manifold gasket, same issue, then changed the head gasket and still the same issue. Is there anything else it could be besides a cracked block?

Read that it could be a crack in the exhaust manifold, when I had it off I looked at it and didn't see anything obvious that looked like it could be the issue. Does anyone know where these typically fail when they do?

Also, if I need a block where can I find one? I have been looking around and haven't really found anything other than some outrageously priced rebuilt motors.

Thanks in advance for the assistance have found this forum to be a great asset when troubleshooting things.

Dan

 

[Anders67]

Re: 1996 Sport Jet 120 water in Cylinder

Hi. Did you look closely on the gasket surface on maifold and block , so it was ok?. Same on head and block?.


Do you get whater in the cylinder when driving on lake ore when hooked up to garden hose. And do you hook up to the black hose from pump to manifold? (cooling whater). Not the one connected to head-top? ( just for flushing).


Regards

 

[batboat11]

Re: 1996 Sport Jet 120 water in Cylinder

I have a 1996 120 sportjet and had the same problem, i found a slight fold in the manifold gasket which allowed water in while i was using the garden hose adapter, i replaced the gasket and cleaned the face and problem went away, hope u find it, Mark. batboat11

 

[hkydan]

Re: 1996 Sport Jet 120 water in Cylinder

Hi. Did you look closely on the gasket surface on maifold and block , so it was ok?. Same on head and block?.


Do you get whater in the cylinder when driving on lake ore when hooked up to garden hose. And do you hook up to the black hose from pump to manifold? (cooling whater). Not the one connected to head-top? ( just for flushing).


Regards

Yes, nothing noticeable on the manifold or the head. Getting water from both the lake and hose. The hose is connected to the manifold with a hose attachment with water running a trickle as described in other posts. The motor becomes hydro locked within about 3 or 4 cranks of the starter. Its not just a little water it seems to be a lot of water.

So today I have pulled and tore down the motor. There is a lot of milky sludge in the motor and 3 of the pistons have a lot of wear/Scuffing on them. I assume its from the water and not lubricating properly. But even with the motor torn down I still don't see anything obvious that would allow the water to penetrate the cylinders and crank. Sure it could be a hairline crack and not easily visible but with the amount of water that appears to be penetrating it seems like it should be more obvious.

Is there another seal or gasket other than head or exhaust that could have failed and allow the water in?

Thanks
Dan

 

[Anders67]

Re: 1996 Sport Jet 120 water in Cylinder

Check the manifold and head. Check so it?s straight and not bent of heat on a steelscale ore flat surface. It?s many channels etc., so check it carefully again. Right gaskets?. There are different types.

Next is to pressure test it someway, ore use developer fluid to see cracks in metal. Manifold and head at beginning.

Next cyl. sleevses not sank in to block ( not sealing to head).

Last, crack in block.

 

[hkydan]

Re: 1996 Sport Jet 120 water in Cylinder

After checking things out I have not found any crack in the block, warped head or anything like that. What I think was going on is there was so much milky sludge in the engine it kept pushing it out the cylinder which became hydro locked very easily. When I pulled the crank out it was covered as well as it was just pouring out after pulling the adapter plate off the bottom of the block. So changing the exhaust manifold gasket probably fixed my problem but there was so much sludge built up, it kept pushing it out the cylinders. Before I changed the manifold gasket there was pure water pouring out of the bottom cylinder, after changing, it was just the milky sludge.

Just my guess anyway..

I have a lot of scoring on the cylinder walls and pistons. Need pistons and some machine work on the block. It appears the Force engine parts are easier to find which leads me to a question. Does anyone know if the Force block will work with the Sport Jet? The block looks identical with the exception of the adapter plate or the plate that mates to the jet. Is the bolt pattern the same? Does anyone know what the difference is? Found a guy that has a Force block and pistons ready to go at a reasonable price.

Thanks

 

[Craighimself]

Re: 1996 Sport Jet 120 water in Cylinder

Hey I just swapped my sport jet 120 parts with the force 120 outboard block, everything went together great, the cdi mounting was a little weird but I made it work, and the opening in the bottom of the block for the exhaust on the force was different than the sport jet. I think the gasket on the base will seal it off but I am having exaust in the water jacket issues right now so who knows, i might pull it and seal the opening.

but yeah the force block was like 40 bucks on ebay, if you use the sport jet crank it will spline right in. mine was all Original bore so my pistons went in great.

No oil pump on the old force blocks so i commited to mixed fuel.

Recirculation system was different as well but I made due

I have a bunch of pics of the swap if your interested.

 

[4shore]

Re: 1996 Sport Jet 120 water in Cylinder

Hi. Did you look closely on the gasket surface on maifold and block , so it was ok?. Same on head and block?.


Do you get whater in the cylinder when driving on lake ore when hooked up to garden hose. And do you hook up to the black hose from pump to manifold? (cooling whater). Not the one connected to head-top? ( just for flushing).


Regards

I know this is an old post but you asked some valid questions. My sj 120xr has done the same thing. I first noticed a damp plug on the lower cylinder #4 as I was timing the motor. I had it in the lake 4 days prior. I had a slow to start then bumped 2-3x it and she was ready for the lake. I did not know what to think of it. It seemed at the time minor but unknown. So I finished timing the engine (per manual) and I wanted to run it to hear how it sounded.

So I hooked it up to a hose connected to the black hose near pump base. Let the water run slowly through the system for 5min. Water was coming out of the lower pump area as normal. I went to crank it and I noticed a slow to crank issue. I bumped over several times and then it would crank. The longer it ran the smoother it became. After a moment or so the over heat alarm came on and I shut it down. I thought that was strange as I did not run it but for 30-60 seconds before alarm and I have not heard this noise before. (I had to look up the sound) I shut the engine off.

An hour later I decided to let the water flow though the engine for a flush as I thought there maybe a clog. ( Did not know top was for flush) I came back to check for water in #4 and water poured out. I then checked all plugs and it was only #4. I then purged the water out by cranking with no plug then squirted a table spoon of 2 stroke oil into the chamber to help against the water.
I know that I had some water at the lake and the hose for sure. Any advice??

 

[hkydan]

Re: 1996 Sport Jet 120 water in Cylinder

From my research water in the Cylinder is typically caused by two things. 1. Exhaust Manifold Gasket 2. Head Gasket. I have also had someone tell me that if you run too much water pressure with the flush kit it will also push water into the cylinder, but not sure on that one.
In my case it was too late and the damage was already done to the cylinders. After tearing the motor down bottom 3 cylinders had scoring with the bottom 2 the worst. The bottom 2 were also out of round assuming all the water was preventing the oil from lubricating.
Been having a hard time finding a replacement Block or someone that can re-sleeve the cylinders.

For you I would suggest replacing the Exhaust gasket and checking it again, try to get as much of the water out of the cylinder as possible.

Good Luck.