Are my fuel pumps bad?

[Pursuit2550]

I recentlly clean out and replaced all the parts that come in the oem kit on my carbs. I did everything by the oem manuall and also did all the syn. From day one the problem has been that its had to start. In my house if it been sitting for 2 weeks lets say, I go to crank them and it had. I primethe bulb (it stays hard) put the choke and crank. It takes it about 5-6 cracks and when it cranks it starts out slow 2-300 rpms and works it way up. When I take it out to the sandbar and I have had it off for 2-3 hours its the same thing, only thing is that when it does start it has a hard time staing on. It will shut off and to crank it again takes a couple of trys. It idles fine (7-800rpms), even when Im docking its fine it wont shut off. Runs perfect on top end 53-5000 rpms. What can it be? I am about to change the fuel pumps since they are the factory ones. They are twin 93 150 Yamahas.

Thanks

 

[rodbolt]

Re: Are my fuel pumps bad?

change the pumps as a maint item and review your starting procedure.
these are NOT prime start engines and require operator interaction,
you MUST use the warm up or throttle only feature and advance the throttle when cold so the engines light off at about 1500 RPM and let in run there 10 20 seconds before idling down.
non-prime start carburated 2 strokes require the operator to advance the throttle/timing and choke it or they either wont start or start very hard.

 

[Pursuit2550]

Re: Are my fuel pumps bad?

Thanks Rodbolt. A buddy of mines told me the same thing but I wantted to make sure. One more question, if the engines idle at 7-800 rpms in the water, what should they idle out of the water.

Thanks

 

[Pursuit2550]

Re: Are my fuel pumps bad?

bump

 

[bustermin]

Re: Are my fuel pumps bad?

you dont indicate WHY you did the carb rebuild, was it just preventive or was there a problem. if it was preventive and you did not have this issue prior to the rebuild the problem is most likley with something that you touched, rather than somthing you didnt touch. i would recheck you carb adjustments.

 

[Pursuit2550]

Re: Are my fuel pumps bad?

Carbs had never been rebuilt so thats why I did it. And it had the problem before the carbs been done. What is the normal rpm difference form the boat in the water and out of the water.
Thanks

 

[rodbolt]

Re: Are my fuel pumps bad?

on that model yamaha mostly no difference in or out of the water for idle speed.