help with 720 engine starting problem

[schultztec]

Hey folks,
I have a problem with my seadoo 720. When its cold it seems to start right up and after riding it for a while it becomes difficult to restart. have to hold throttle wide open for it to start. Once it starts it has no throttle responce (idles but does not respond to throttle). about 10 seconds later it picks up and runs fine.
I have rebuilt both carbs and fuel pump and and have adjusted to SBT recomended setting. I did try turning the low speed needle in an 1/8 of a turn. This did not seem to help. Fuel filters are clean. Fuel selector is clean. Seems to be a rich condition but plug check looks coco brown after low speed check.
Anyone have any ideas.
Thank you
Schultztec

[schultztec]

Re: help with 720 engine starting problem

BTW, I used the stock springs for popoffs.

thx
Schultztec

[frankey01]

Re: help with 720 engine starting problem

When you did the popoff test dd you do a leak down test for the needle and seat valve and did you replace those (needle and seat) when you did rebuild?

[schultztec]

Re: help with 720 engine starting problem

yes sir I did replace the needle and seat. used the old spring that was in the carbs before the engine was replaced. However I did not do a leak down test because i do not have a pop off guage. I was hopeing since i used the factory springs pop off would be close ??

thx
schultztec

[frankey01]

Re: help with 720 engine starting problem

should be close what are your settings as far as hi and low speed screws?

[schultztec]

Re: help with 720 engine starting problem

high speed it all the way in or 0 (per sbt chart) and low speed is 1 1/4 from there I leaned the low speed down 1/8 in but did not seem to help. It sure seems like my pop off pressure is to low. I may have to purchase a guage.

thx
Schultztec

[frankey01]

Re: help with 720 engine starting problem

it would be best to do so as I am not sure what you had before it may have had the wrong spring in it and not knowing what it is makes it hard to tell you to do this or that

[schultztec]

Re: help with 720 engine starting problem

yeah, i guess i will have to do the test. The carbs were all stock but i wonder if the sprins could have gotten worn out from use. Hence lower pop off pressure ??


thx for the replys
schultztec

[frankey01]

Re: help with 720 engine starting problem

it is possible do you happen to know how old the old spring was or is?

[schultztec]

Re: help with 720 engine starting problem

Not 100% sure but i would bet it was original factory 1996

[schultztec]

Re: help with 720 engine starting problem

The funny part is the ski is an HX, and It is my first ski. I have yet to be able to get back on the stupid thing when I fall off. So when its hard to start It makes it all the more difficult. HOWEVER, my neighbors get a kick out of watching me flounder around in the water trying to re-board the thing for 20 minutes at a time!!

Schultztec

[frankey01]

Re: help with 720 engine starting problem

definitely time to change the springs and check pop off

[schultztec]

Re: help with 720 engine starting problem

Do i need to pull the carbs off to do the test ??

[frankey01]

Re: help with 720 engine starting problem

To do it properly yes you will remove the diaphram and spray some wd40 on ithe valve then put the hose on the gauge on the inlet fitting of the carb then with your finger on the outlet fitting pump the gauge til it "pops" the needle also check the leaking by making sure that the carb can hold 10 psi for 5 minutes really just make sure that it holds pressure for more than a few minutes without losing pressure rapidly.

[schultztec]

Re: help with 720 engine starting problem

great thx for the info