Petcock in prime position.

[RD56]

Quick question...can be yes or no. Will an 85 FJ  flood your garage floor with the petcock in prime position and carbs perfectly serviced and operating properly. In other words will gas stop running when floats are full or will gas continue to flow filling bowls to overflow. I have searched and seen where it is not recommended to leave in prime position but I am wondering if overflow will always take place and flood crankcase while sitting. Thanks .
Rick

[racerrad8]

If the carbs are functioning properly; the needle seats and o-rings sealing the seats are functioning properly then the fuel flow should be stopped there regardless of the petcock position.

Randy - RPM

[red]

Quick question...can be yes or no. Will an 85 FJ  flood your garage floor with the petcock in prime position and carbs perfectly serviced and operating properly. In other words will gas stop running when floats are full or will gas continue to flow filling bowls to overflow. I have searched and seen where it is not recommended to leave in prime position but I am wondering if overflow will always take place and flood crankcase while sitting. Thanks .
Rick

Rick,

Sounds dicey to me.  There is no fuel filter on the '85 so with the petcock in the "prime" setting, just a speck of rust or grit could cause one fuel bowl to leak, even though the carbs are "perfect."

Outside, it's a risk to the bike, but in a garage, everything in there is at risk.  If the garage is attached to the house, the house is also at risk.  If your petcock has a problem, consider what you are risking vs. what you are "saving" before you roll the dice.

Red

[RD56]

Thanks Red...I was asking for a friend who has a 750 / 3cyl with vacuum petcock. I was suggesting that he look at needle seat orings as well as petcock. No, I don't like molitov cocktails in my garage either. Thanks.
Rick

[FJ1100mjk]

There is no fuel filter on the '85

Red

Maybe not in the traditional sense. However, there is a column-shaped fine mesh "filter" inside of the fuel tank attached to the face of the petcock, and individual mesh (coarser) caps above each float needle seat that do a decent job of filtering rust, gunk etc.

[Fj.itis]

I must say the inside tank filters do an ok job of filtering but stuff still gets through, dont ask me how but it does. Ive also got an inline filter between tank and carbs and i see the specs in that filter so it can get through.
You can get away with it short term but long term use i guess your just asking for fuel to be emptied over your garage floor.

[airheadPete]

Um, just checking...
Your friend doesn't have a gas water heater in his garage, does he? 
It's not unusual.

[Pat Conlon]

Reminds me of the old saying:
How many times do you tell someone what they need to do..?
One time? Three times? (most common answer)
Correct answer: As many times as it takes, for that person to fully understand what it is you're saying.
Once they understand, either they either follow your advice or not...(free will)

Rick, I hope you relay to your friend our (very valid) concern about the danger of leaving the petcock in the Prime position.

Using Prime to get home is one thing. Entirely appropriate. Leaving it in Prime is dangerous.

You have been warned...

[RD56]

Reminds me of the old saying:
How many times do you tell someone what they need to do..? One time? Three times? ( common answer)
Correct answer: As many times as it takes for that person to fully understand what it is your telling him to do.
Once they understand, either he either follows your advice or not...(free will)

I hope you relay to your friend our (very valid) concern about the danger in leaving the petcock in the Prime position.

Using Prime to get home is one thing. Entirely appropriate. Leaving it in Prime is dangerous.

You have been warned...

The reason for the post was more of a diagnostic one. My brother was helping a guy with a late '70's Yamaha  750. He discovered a tremendous amount of gas in the oil and diagnosed the petcock issue. I think those bikes had switched to Mikuni CV's by that time and I told him to check the needle seat o-rings. Even without reading the posts regarding gas leaks, I wouldn't recommend to my worst enemy that he/she leave the petcock in the prime position, well maybe one. I was just curious that if one ever did that by mistake, that a properly serviced carb with new o-rings would stop the flow. Thanks for your concern, that's what makes the Forum so worthwhile.

Rick