prime starter assy.

[handle]

06 yamaha f40 TLR with 703 controls, what exactly does the Prime Starter Assy do and when does it activate? I do not believe when the key is in the on position and you push it , anything happens. Atleast mine does not respond.

 

[robert graham]

Re: prime starter assy.

The prime start system is a totally automatic mixture enrichening device containing a wax pellet that expands and shrinks with the ignition switch on/off, opening and closing a valve that feeds raw fuel into that carb. The "push-in key" feature on your 703 control was used to operate a choke on earlier models, but does nothing on prime start models. The prime start on my 1999 Yamaha 90c has been totally trouble-free since new, so I've just left it alone to do it's job...no problem, so far!

 

[99yam40]

Re: prime starter assy.

Good explanation Robert,
except it is when motor is running the battery charging system sends the voltage to heater unit not just with key on. And it send extra fuel into the intake not the carbs

 

[handle]

Re: prime starter assy.

Appreciate the input, couple of questions. I assume the prime starter activates on start up and how do you test this. It looks like a vacuum hose that feeds the top of the intake manifold, feeding just one cylinder, but is attached to all three carbs. Not quite sure how it works.

 

[99yam40]

Re: prime starter assy.

From what I was told and understand ffom looking at mine for a long time.
The one hose hits a nipple that leads to passages that hits all 3 intakes.

There is not liquid fuel that runs through that hose, but a mix of fuel from prime start enrichment system and air sucked off the middle carbs float chamber's vent on my C40. not sure about your F40

 

[Ldavidgrover]

Re: prime starter assy.

If working properly when you start you engine it will get hot.