Hot start problem with 2010 Ultra LX

[Rescue1]

I had this issue with an older 12F as it had the same engine and setup just a smaller stroke. I tried a new water temp sensor but it would still do the no start on hot thing. The temp sensor is nothing more than a thermistor, and as the engine gets hotter the resistance will decrease. I added in a 100k resistor and a true waterproof DPST switch that would put the resistor inline with the sensor and ECU when I needed it too, then mounted the switch in the storage box. When activated, the ECU would see a much higher resistance which tricks it into allowing more fuel into the MAP table and it would start. Thinking back, I think there was a thread on PWCToday about all of this, but I can't seem find it at the moment.

[coopersfool]

They are kind of weird parts bin mashups, so its not a 100% 15f or Ultra. They use different timing wheels, cranks, and cases vs the 15f.The lx uses use ultra style ecus rather than the single plug mitsubishi setups the 15f uses.

Sean

OK Thanks Sean

Is there any fix for this?
Do i get a 2013 Temp sensor or
is there a modification for the exisiting?
Cheers

[coopersfool]

Hi Rescue is this something a auto spark would do ? i am amazed that no kawasaki dealer seems to know anything about this.

Yet it clearly is a problem
Anyway thanks for your reply

[Rescue1]

Hi Rescue is this something a auto spark would do ? i am amazed that no kawasaki dealer seems to know anything about this.

Yet it clearly is a problem
Anyway thanks for your reply

I don't believe an auto spark would help here. The main issue is the ECM/ECU thinking things are hotter than they actually are, and giving a super lean fuel mixture. The resistor will trick it into thinking otherwise and you will get the proper amount of fuel, then start up.

[coopersfool]

I don't believe an auto spark would help here. The main issue is the ECM/ECU thinking things are hotter than they actually are, and giving a super lean fuel mixture. The resistor will trick it into thinking otherwise and you will get the proper amount of fuel, then start up.

Thanks Rescue
Do you happen to have a copy of the diagram that spades did?

I cannot access it on PWC

Thanks Shaun

[coopersfool]

Well I got the resistor switch and the momentary press button fitted but no good the ski has trouble cranking in the water it does start with booster cables though i have replaced the battery with a Deka sealed battery as per recommendation and the starter motor was replaced last year.

The funny thing is it cranks so easy out of the water it is so frustrating don't know what to do next?

Thanks Rescue
Do you happen to have a copy of the diagram that spades did?

I cannot access it on PWC

Thanks Shaun

[First Ultra LX]

Hi Mate,
I have had this problem also.
It seems the most likely problem with my ski and I suspect yours is a corroded exhaust/ manifold.
I have an 08 ultra lx.
There are many examples of this on a FB page I follow Kawasaki jet ski owners.
Another fix is to lift one of the cooling hoses in higher in the ski an cable tie it up in place.
This didn't fix mine and I am contemplating removing the exhaust an having it pressure tested by Brisbane Kawasaki.
I'm hoping it isn't the case as a new exhaust is pretty pricey.
I have already fitted a new water temp sensor but it made no difference. The only time my ski has this issue is after riding 2 or 3 up and stopping or while attempting to fish with the esky/cooler on after stopping on the water for a few mins.

I bought this ski hoping to Spearfish from it but I don't know if this will be possible even after the repair because it seems to be common with ultras pre 2016 I think.
I would love to hear back from Tony R but I think he may not be on this forum any longer.
Good luck Tim

[coopersfool]

Hi Mate,
I have had this problem also.
It seems the most likely problem with my ski and I suspect yours is a corroded exhaust/ manifold.
I have an 08 ultra lx.
There are many examples of this on a FB page I follow Kawasaki jet ski owners.
Another fix is to lift one of the cooling hoses in higher in the ski an cable tie it up in place.
This didn't fix mine and I am contemplating removing the exhaust an having it pressure tested by Brisbane Kawasaki.
I'm hoping it isn't the case as a new exhaust is pretty pricey.
I have already fitted a new water temp sensor but it made no difference. The only time my ski has this issue is after riding 2 or 3 up and stopping or while attempting to fish with the esky/cooler on after stopping on the water for a few mins.

I bought this ski hoping to Spearfish from it but I don't know if this will be possible even after the repair because it seems to be common with ultras pre 2016 I think.
I would love to hear back from Tony R but I think he may not be on this forum any longer.
Good luck Tim

Thanks for the info Tim I have actually replaced the exhaust also and you are right they are pricey.
I looked on that FB page so I might ask the question there also.
I am only using the ski with one person on it but might try the exhaust one way valve and the hose trick.

It is in the local kawasaki dealer here in Perth WA but they are a little stumped also.

Will post a reply if they do fix it
Cheers

[First Ultra LX]

Ah all the best with it.
Looking forward hearing the results.

[STEALTHRHINO]

Did you guys every find a solution to this problem? I have a 2019 Ultra Lx and does the exact same thing. Use it for fishing and a couple of months ago had a rough start but on the weekend had to drift for half an hour before the ski would start back up. Just wondering if there was a solution to this problem at all? Cheers