Updated - 1996 XP starts and idles now but dies when throttle given

[shattered00]

Hello all,

I have finally got one of the 1996 XPs fully assembled. It cranked last weekend without the jet pump on and I did not let it run for long since the driveshaft was slightly loose. I put everything together and the impeller spins freely. The ski will keep trying to crank but does not turn over. The carbs appear to be pulling fuel as there is fuel in the line going from the separator to the carbs. The negative terminal cable gets hot on the end when I disconnect it after trying to start. This is for a newly rebuilt engine that has never run since being rebuilt aside from last weekend. Here is what I have done.

- New spark plugs gapped properly
- New fuel lines
- New fuel selector and fuel separator
- Rebuilt carbs with Mikuni kit
- Bypassed everything and ran the fuel line to the carbs straight to a gas can and still nothing
- Used dielectric grease on all points where a starter cable connects to either the battery terminal or the starter

I attached a video link so that maybe someone can tell what is happening from the audio alone? Using the choke and depressing the throttle slightly did not have any noticeable affect.

Thank you for your help.

 

[mikidymac]

If you have fuel and compression then you need spark to fire.

Did you verify you have a good hot spark?

If the cable is getting hot either the cable or the connection is bad. Typically these cables go gad from the inside out so it might not be obvious.

 

[shattered00]

I have not verified spark. I just looked up how to do it. The "instructions" say to leave the spark plugs in the holes and remove one boot at a time. With the boot just above the spark plug but not touching the plug, look for an arc while trying to turn over the engine. Is this a valid way to test them?

The ski has 150 compression in each cylinder.

I will look into the battery/starter cables being corroded as well.

 

[mikidymac]

You can either buy a spark tester that goes on the plug cap or just leave the plug in the cap and ground the metal of the plug to the engine and look for a spark.

 

[shattered00]

On crappy phone. Sorry in advance. One spark plug tested 10kv and the other 2kv. Bad spark I think?

 

[esahlin]

Are your plugs fouling? Are they soaked with fuel after you crank it? Do you have some dry plugs to try?

Take the plugs out and crank it to blow any excess fuel in the cylinders out. Fouled plugs and too much fuel will cause a no start. Try different dry plugs after you think the cylinders are dry.

Happened to me last week for some reason the carbs were dumping fuel. It showed I had spark but still wouldnt fire. There was so much excess fuel in the cylinders that I took the carbs off the intake and cranked the engine and it started briefly with the carbs off the motor.

 

[shattered00]

Update:

There was slight spark in spark plugs but no signs of fouling and very little fuel if any in the holes where the spark plugs go. The fuel line to the carb and the fuel separator had fuel in it though so I wasn't exactly sure of the problem. I took the rubber boots of the plugs and cleaned what I could and put them back on with about the same spark (consistent spark but the tool from AutoZone would only show a spark with a very small gap between the two ends and any time I tried to widen it slightly the spark would not appear).

I ended up pouring a slight amount of fuel in both the spark plug holes and the carbs and the ski cranked so it was definitely a fuel problem. The ski now idles really well but as soon as you give the ski throttle it dies. If you give the ski throttle while pulling out the choke it will sometimes rev up but dies not too long after. I have started the ski over 20 times so I know it is pulling fuel on its own now and not just from what I poured in the carbs/spark plug holes. I also see that oil is being pulled into both of the small hoses that feed into the pistons as well as the two large oil lines.

I have read numerous threads on this dying while giving throttle problem and it seems my options are:

1) Pop off pressure is off? - unsure how to test at the present or what this is
2) Carbs are running lean - I did notice that there is no smoke coming from the exhaust like my 95 does...
3) Air leak - I have clamped down everything as tight as I can with the hose clamps - carbs have the gaskets on
4) Raves are dirty - I have cleaned them

I am going to try and find a manual to adjust the carbs and go from there. Any other suggestions would be much appreciated. Thanks as always!

 

[mikidymac]

I would suggest rebuilding the carbs per my carb rebuild thread.

 

[esahlin]

That's frustrating: I would do as mikidymac said above and pull the carbs and go through Mikidymacs carb rebuild tutorial and pay extra attention to the three transition holes in the carb body and cleaning them out with carb cleaner. As the throttle blade sweeps open fuel is fed through these three transition holes until the the throttle is opened far enough to be on the main jet circuit.

You can make an easy pop-off pressure tester from an air tool pressure regulator at Home Depot or harbor freight …..you need an air compressor though.

Did you get new Mikuni brand needle and seats? Everyone here recommends them.

Take the jets out of the carb body and spray carb cleaner through the jet passages in the carb.
Make sure your carb synchronization link (the adjustable link that connects the two carbs throttle levers) is adjusted so that both carbs are opening their throttle blades at the same time.

Inspect carb base gaskets for possible leak places.

Mikidymac's carb rebuild "how to" is excellent. Hopefully this second carb cleaning/inspection will fix your problem.