Fuel Switch - Prime Position

[guitar guru]

So as I understand, the "Prime" position defeats the vacuum of the fuel tank that normally exists when switched to "on." This allows fuel to go into the engine while parked, and I've been told it's good to do this if it's cold out or the bike's been sitting dormant for awhile.

My question is if it's ok to leave the switch on "prime" all the time (except when taking the tank off the bike of course) or if there are consequences to this action. If so , what will happen.

Also, if any of the other info I have about the "prime" position is incorrect then please correct me.

[jmillheiser]

the purpose of the prime position is to get the bike started if its been sitting awhile. It may flood the carbs and possible leak if left on.

[guitar guru]

Are you sure, cause I've left mine on occasionally overnight on accident and while I was riding. It still started up when I needed it to, so I assume it wasn't flooded.

[TechTMW]

It may be OK now, but if anything gets into the carbs or there is a fault with your float or needle valve, you Will get overflow (at best) or you could flood a cylinder if one of your overflow tubes is blocked (At worst.)

Flooded cylinder means Hydrolock, and a possible complete engine rebuild.

Best just to leave it in the "on" position overnight - it's cheap insurance.

[guitar guru]

Here's my problem though; The bike seems to start up easier and so far more dependably when the fuel switch has been in the prime position for some time, especially when it's cold out. So now I don't know what to do.

[Spiff]

The bike seems to start up easier and so far more dependably when the fuel switch has been in the prime position for some time, especially when it's cold out.

Are you using the choke when you start up your bike?

Gotta do this, especially when it's cold. Give the throttle a twist, too, while you're pressing down on the starter button.

You should not have to use the prime switch to get your bike going. If you do, you need a mechanic to check it out.

[Lion_Lady]

My old GS250 would drip gas if left in the prime position.

P

[guitar guru]

I definitely always choke it full when starting up unless it's been sitting for less than a half hour. But today and yesterday it started fine with the switch in "on" position even at 10:00 at night. So I don't know what the deal is, or if there is a deal for that matter.

How long would you think it would have to sit dormant to necesitate my using the "prime" position? It sat for five or so days once without being run and didn't start right up when I needed it to.

Maybe there are certain time God just doesn't want me riding.

[TeeMan]

I have a 92 Suzuki GS500EN and found the exact thing. It was pretty cold starting and once I left the switch on PRIME it fired up perfectly (it sat for a week in prime).

The guy I bought it from came over to help me fix something and told me what everyone here is saying...

I only ride the bike once a week while I'm "learning" so its nice for it to fire up right away but I also don't want to risk flooding or worse, a pool of gasoline.

What's a newbie to do?

[TechTMW]

Some bikes are just cold-natured like this.

I had an xj650 that did exactly the same thing. The most convenient way to deal w/ this problem (IMO) is to install a transparent inline fuel filter. When you go out to the bike in the morning, switch the bike to prime, and watch the filter fill back up w/ fuel. When the filter is full, you know the carbs are good to go and you should have no problem starting regularly.