spx 98 - issue to start when hot

[Ardilla]

Hi

I have an issue to restart when hot (after 20 minutes) my spx 98 787. I rebuilt the carbs and cleaned them. When cold it is starting pretty well with starter. When it is hot and we try to re-start low chance to restart it. to run it again it needs to be with starter + WOT for 2-3 minutes.

Any idea where or how to fix it?

Thanks
FC

 

[bigJake]

if the problem is you run it, then let it sit for a while then it won't restart, probably leaking needle/seat. Did you use genuine Mikuni parts for the rebuild. If not you need to do it again.

 

[Ardilla]

Thanks for the reply.

Ski run fine in sea but cannot restart when hot. Sometimes with choke and full throttle during 2-3 minutes it restart but normally not. On the trailer or garage after 1h no issue to restart.
Yes I used oem mikuni parts.
Is mikuni supplying only seat and needles + springs. The other parts looks to be ok as i changed it (I did not change needles and seat but cleaned it and looked really nice).

Do you think high and low adjuster can have an effect? I adjusted it according to service manual.

Any other source creating this problem?

Thanks
FC

 

[Mem1guy]

You need to replace the needle valve with OEM Mikuni. Did you do a pop-off test?

 

[POPPS]

check out RV clearance,,,excessve clearance can also create your symptoms

 

[Ardilla]

No, I do not have tool to perform the pop off test but looks that next step is to change needles, valves and spring isn't it?

Regarding Rave Valve clearance any way to fix them? I cleaned them but problem still the same. Do I need to change the RV?

 

[POPPS]

You. Need to measure the clearance between the rotary valve and the engine case.