1995 SPX Not Starting

[kenkuntz]

Hi all,

New to PWCs completely, but trying to get into the hobby with some used SeaDoos. I have a 1995 SPX that is cranking but not starting. Today, I rebuilt the dual carbs just to make sure nothing was corroded/gunked up since the previous owner had them. I didn't see any major concerns, everything looked pretty clean. After re-installing, I can't get it to start up.

I took off the pulse line from the carbs and tried to crank the engine a second or 2.....I do feel slight pressure coming out, but not sure if its enough to make the fuel pump work correctly. Took the gas line off the carb, and not seeing any gas drip out.

Couple questions, but maybe I'm not asking the right one:
- how to test/know if the pulse from engine is adequate?
- how to test fuel pump is functioning properly?
- what else could be the cause?

The previous owner demonstrated that the engine will start if fuel sprayed directly into the intake, but it will not remain running. Could someone give me some things to look at and in which order makes sense? Again, I'm new to the hobby, and small engines in general, but I'm eager to learn!

Thanks!

 

[kenkuntz]

To add,

I took off the fuel line from the carb and cranked it. I expected some kind of suction at the carb valve, but didnt feel anything. Is that expected? Maybe not enough pulse from engine? The pulse felt very light...but I have nothing to compare it to.

Possible issue with engine not producing enough pulse? If so, what's next?

 

[mikidymac]

Did you rebuild the carbs with genuine Mikuni parts and new needles and seats following the Carb Rebuild sticky?

 

[kenkuntz]

I can not confirm the parts type......the rebuild kits were passed on by the previous owner. However, there was not any new needles in the kit, so had to use the old ones.

 

[kenkuntz]

I dont mind to purchase the Mikuni rebuild kit and needles......just want to make sure that other note on the Pulse pressure does not cause concern, or if its expected. It felt somewhat faint, but again I'm not sure what's expected.

 

[mikidymac]

You won't feel a lot on the pulse so as long as your compression is good and rotary valve is working I wouldn't worry about the pulse signal. I would worry about the carbs being correct.

 

[kenkuntz]

ok, thanks...I'll try a new kit. So I should get the "MK-BN38/44-SPR" kit? and which needles? Also, which and where do I get the gaskets between carbs and manifold?

 

[mikidymac]

Yes those are the correct kits. Your 1995 SPX ski uses the 1.2 needles and seats.

As far as the correct spring for yours, the best answer is I am not sure. I am making a list of all the Seadoo Pop-Off springs and your model is one of the few that has been a mystery and I am trying to get an OEM spring to see what it actually matches to as Seadoo used lots of different numbers for the same springs.

 

[kenkuntz]

awesome, thanks...maybe with some testing i can something to work.

another quick question: if I had a working set of carbs, and pulled off the fuel line...would i expect to feel noticeable suction at the carb inlet?

 

[danielw05]

ok, thanks...I'll try a new kit. So I should get the "MK-BN38/44-SPR" kit? and which needles? Also, which and where do I get the gaskets between carbs and manifold?

You will more than likely be able to get the gaskets between carb and manifold at the same place you buy the Mikuni kits. I was sent the wrong gaskets so ended up going to an auto parts store and purchased fuel gasket material to make my own in order to get running for the weekend. In my 94 spx, I was having the same issue. The 94 spx was my first pwc purchase ever and had never worked on one. Lurking on this forum for the past month helped me get it going by rebuilding carbs with Mikuni rebuild kits (see sticky thread and pay special attention to popoff as well as low and high speed settings), put a new o-ring and filter on the fuel/water separator, cut back one of the spark plug wires and installed new spark plugs, and put in new fuel. If you have gray fuel lines, you will need to replace them. If ordering parts, you may go ahead and get a new petcock for the fuel selector. Have you checked compression of both cylinders?

 

[kenkuntz]

You will more than likely be able to get the gaskets between carb and manifold at the same place you buy the Mikuni kits. I was sent the wrong gaskets so ended up going to an auto parts store and purchased fuel gasket material to make my own in order to get running for the weekend. In my 94 spx, I was having the same issue. The 94 spx was my first pwc purchase ever and had never worked on one. Lurking on this forum for the past month helped me get it going by rebuilding carbs with Mikuni rebuild kits (see sticky thread and pay special attention to popoff as well as low and high speed settings), put a new o-ring and filter on the fuel/water separator, cut back one of the spark plug wires and installed new spark plugs, and put in new fuel. If you have gray fuel lines, you will need to replace them. If ordering parts, you may go ahead and get a new petcock for the fuel selector. Have you checked compression of both cylinders?

I havent personally checked the compression, but previous owner before said it was good.

 

[Seadoo timebomb]

On that old of a ski, check the fuel lines, fuel selector valve and fuel strainer for trash. The fuel selector is extremely common for filling with corrosion on those. You symptoms point directly to fuel delivery to carbs. Get a hose bulb like used on outboards. Plumb it in to the line going down to carbs from fuel strainer. Remove the return line from carburetors. Pump fuel from outside source until return line is squirting. Replace return line. Now you are ready to start up the engine. If it starts right up, then your lines need addressed.

 

[kenkuntz]

One find so far, the fuel bowl did not have a filter at all. Was what smelled like a small puddle of gas at the bottom, with some black flakes (maybe hose material?)

How do you test the fuel selector/petcock? Or should I just order a new one?

 

[Seadoo timebomb]

New ones are cheap. Go ahead and remove it and look in the hose barbs. They are likely plugged pull of corrosion. I used to bother with cleaning them, but old fuel kills the rubber inside and they leaked.

The older ones can be disassembled, but usually not worth it to find out they leak.

You need to get the inner screen filter for that fuel strainer too.

 

[kenkuntz]

Inner screen filter? See attached pic, the cylindrical filter is what I found missing altogether. Is this the screen you are talking about?

 

[danielw05]

Inner screen filter? See attached pic, the cylindrical filter is what I found missing altogether. Is this the screen you are talking about?

yes