Anyone have any luck with fixing Stx hot start issues???

[gixxer1kr]

I've been dealing with it for a while anyone have any luck with a fix. Maybe something blocked somewhere or something. Only does it randomly when hot and off for a while. After a lot of talk with a very knowledgable mod on her I am thinking re flash and newer sensors but is there something I should be checking 1st. All I did was replace the sensor on the header and had a heat sink made which helps but not the fix. Just don't want to be without my ski. Very limited season her.

[Spades]

I did it last year adding resistance during startup only using a momentary switch and resistor. Ive yet to try it though because the hot start problem never came back... Thinking outside the box, has anyone tried opening their gas cap to relieve the pressure when the problem occurs? Several of my 2 stroke skis experience similar hot starting issues. Always seems to happen towards the end of the riding day, and the only thing I could think of was because the fuel level was lower. Most of them had primer kits installed so id just give a couple squirts and it would fire right up, but my Seadoo RX didn't have a primer and my solution was to open and vent the gas cap to get it to fire up. I know the 4 strokes have EFI but may be worth a try

[gixxer1kr]

It's the temp sensor. Only thing that works is water on the one on the manifold.Spades how did u set up the resistor. Any write ups on it. Thought of that too. I really wanna do the 2015 reflash but that bottom sensor looks like a bitch to get to.

[Spades]

Here is a schematic I drew up of it. Using a normally closed switch so when the switch is depressed the circuit is open, forcing the current to pass through the resistor, thereby "adding resistance" which is what is happening when pouring water on the sensor. When the switch is released you close the circuit, the current takes the path of lesser resistance (through the switch) bypassing the resistor as if the resistor isn't there, and ski will run on sensor resistance only, just as stock.

[gixxer1kr]

Any pics and where u got the stuff

[Spades]

I don't have any pics, but its just a 1/4 watt 20K resistor and a switch from any electronics store. I guess you could go with a typical toggle or rocker type switch but it leaves the possibility of forgetting to switch back after it fires up. With a Momentary style there is no forgetting

1. Cut one of the sensor wires, doesn't matter which one
2. Place the resistor in series /inline and solder to the wire you just cut
3. Connect the switch in parallel to the resistor
4. Mount the switch. I put mine in the little compartment
5. Resistance test the connector. You should see it add 20K ohms to the original reading when the switch is depressed

Temperature to resistance chart is as follows:
68 degrees 293K
122 degrees 78.5K
194 degrees 18.1K
212 degrees 13K

[gixxer1kr]

Nice. Quick and cheap. I think I'm gonna go this route. 10 dollars and a little soldering.

[Spades]

Great. Let us know the results

[gixxer1kr]

I definitely will but by looking at the resitance numbers on the sensor. When it's reading too hot that 20k resistor will tell the ECU it right is in the middle of the temp range ��

[Spades]

Yes that is the idea. Similar to pouring water on the sensor, as the sensor cools down the resistance rises accordingly and suddenly your ski is able to start again. The added resistor will simulate the same thing without having to open up the seat anymore, and when you release the switch it goes back to running on only sensor resistance again, just like stock