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1997 Seadoo GTI 720 Fouls front spark plug with heavy deposits????

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chrisorbics

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I reciently bought this 1997 GTI and my fiancée loves it.

The problem I am having is that it goes through spark plugs on the front cylinder. It gets a heavy deposit and then misfires. I had to change a plug on the water today and then rode another 45 minutes with no issue. Got to the dock and while I was flushing it the idle went low and engine started to shake again like a mis.

Here comes another plug but why is it doing this?

When I got this machine the oil injection was stuck wide open and not hooked up to the cable. That has been fixed and I keep and eye on it. It used to smoke like crazy. I also cleaned the carb and replaced a few gaskets.

When the spark plug is clean it runs like new. Before today it had about 4 hours on the plugs without issue. Basically I was changing the plugs every 2 rides.
 
So do you think the plug is oil fouling or is it aluminum from the piston? Compression check is in order if not done already and if that cylinder is getting tons of oil (too much) there might be a crank seal leaking but it would be a smoker I think. A leaky crank seal will also tend to flood the crankcase with oil while the ski isn't being used as the oil leaks from the RV drive gear area past the crankshaft seal.

Also, make sure the oil injection nozzle isn't gummed up, there's a ball and spring check valve built into them. Carburetor cleaner and air will get 'em clean.

Which plugs are you using? BR8ES

This is a single carburetor motor, sounds like. Check and make sure the high speed mixture screw is set correctly, sometimes premature fouling is just b/c the mixture is too rich.
 
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compression is 124(which is cylinder in question) and 134psi in the back. I know these numbers are low but it runs like new until the plug get dirty.
 
So do you think the plug is oil fouling or is it aluminum from the piston? Compression check is in order if not done already and if that cylinder is getting tons of oil (too much) there might be a crank seal leaking but it would be a smoker I think. A leaky crank seal will also tend to flood the crankcase with oil while the ski isn't being used as the oil leaks from the RV drive gear area past the crankshaft seal.

Also, make sure the oil injection nozzle isn't gummed up, there's a ball and spring check valve built into them. Carburetor cleaner and air will get 'em clean.

Which plugs are you using? BR8ES

This is a single carburetor motor, sounds like. Check and make sure the high speed mixture screw is set correctly, sometimes premature fouling is just b/c the mixture is too rich.
Click to expand...

Like I said. When I got this wave runner the small cable that runs from the carb to the oil injection was not set up right. The cable was not run through the black plastic sleeve elbow and the arm on the oil injection pump where the cable connects, was unwound about 360 degrees. It is supposed to be under spring pressure.

Someone must have taken it apart and not re-assembled it correctly previous to my ownership. The arm did not even move with the throttle. It smoked really bad.

Could this be causing my issue even though I fixed this. Also I need to look up how to properly adjust the oil injection because I just set it up so that it worked. It might still be sending too much oil but why to just one cylinder?

--Where is the oil injection nozzle located? I will clean it. What would that do if it was dirty?

--Yes I am using BR8ES plugs.

--Yes this is a single carb. I should set the high and low screws to the original specs. If anyone knows what they are let me know.

--If the carb was running rich wouldn't both plugs be crappy or would one cylinder get the brunt of it and the second cylinder get the left over?
 
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Post a picture of the bad plug.

The oil injection nozzles are on the intake manifold the wo small 3/32" lines from the oil pump feed the nozzles.
To adjust the pump with the idle set correctly and the engine off the line on the oil pump arm needs to align with the line on the pump body. Google search will show all kinds of pictures of this.

What oil are you using?

Does it smoke a lot when started after sitting a few days?
 
Post a picture of the bad plug.

The oil injection nozzles are on the intake manifold the wo small 3/32" lines from the oil pump feed the nozzles.
To adjust the pump with the idle set correctly and the engine off the line on the oil pump arm needs to align with the line on the pump body. Google search will show all kinds of pictures of this.

What oil are you using?

Does it smoke a lot when started after sitting a few days?
Click to expand...

Ok I will get some pictures.

I don't think it smokes more when it sits but it has not been started since yesterday So I will start it tomorrow and see.

I have to check the adjustment for the oil injection because there is a spacer on the cable going from the carb to the oil pump. Someone obviously put this there.

I am using Pennzoil marine synthetic blend.
 
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First off Pennzoil is wrong for your ski and could be causing some of the deposits. Never use a TCW-2 or 3 in a Seadoo. Yours requires any API-TC rated oil.
 
First off Pennzoil is wrong for your ski and could be causing some of the deposits. Never use a TCW-2 or 3 in a Seadoo. Yours requires any API-TC rated oil.
Click to expand...

Well I have been using that oil in my other seadoo with no issue. Funny, the other guy at my dock uses Walmart oil and I thought that this Pennzoil was much better.
 
First off that oil is not for a rotary valve engine. Second it is known to make crank seals leak and it does not lubricate as well. Seadoo tested all the oils and there is a reason they require API-TC oil.
The seadoos put out more power per cc than any of the watercraft thus are working much harder and need a specific oil.
You can run what you want but the facts are you should not be running it an any seadoo. This could be some of the cause of the deposits you were asking about.

Just because people do something doesn't make it correct. I am only saying this because I want you to enjoy your ski and keep another seadoo on the water. I am not trying to sell oil.
 
Ok I was doing some reading about oil and it seems like a lot of people use the amsoil pwc two stroke. Which api-tc oil is the best value?
 
Also me and my fiancée went out the other day and the gti is still having an issue but is not creating huge deposits on the front spark plug since I properly adjusted the oil injection. It missing fired and I changed both plugs. (plugs looked more wet and black than anything). It was running good till for over an hour until we were coming out of a no wake zone. my fiancée went to get on plane and no power along with a misfire. after a little while it started to run correctly and go fine. Then some junk got in the jet drive and it started doing it again. I was on my gsx so I will have to take out the gti myself to confirm.
 
I just buy the Seadoo oil Ann get it cheap because I buy so much.
Amazon has it with free shipping.
The 720 and smaller engines are fine with the Seadoo white bottle mineral oil. The 787 and 951 need the full synthetic yellow bottle Seadoo oil.
The yellow can be used in both as well as Amsoil Interceptor.
 
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