1998 Suzuki Quadrunner LT-F250 Gasoline in crankcase

[Parham]

I just bought this a couple of weeks ago.  The oil sightglass was FULL. When I opened the fill plug, oil/gasoline LITERALLY gushed out and flowed for several seconds...FROM THE FILL PLUG!  I drained it, changed the filter (no metal bits), and refilled with new oil.  Opened up the carb and cleaned the float needle.  Blew into the fuel inlet while manipulating the float and it seems to work.  Buttoned everything back up and it runs good.  Now my question...was the fuel getting into the engine because of a stuck float needle or is there something else wrong?

[Gwbarm]

Sometimes gas can leak past a worn float needle and seat you should replace it. I usually turn my gas off when not running and its going to be sitting for a while. I got used to doing that with my lawn tractors, briggs are notorious for that.

[Mech]

You need to have a look at your fuel tap and see if it has a vacuum hose on the back of it. If it has a vacuum hose then that tap has no off position. In normal use you leave it on run or reserve and when the motor stops the lack of vacuum closes off the tap, when it fires up the vacuum opens the tap. The middle position of the tap is called prime and it's on all the time, it's for filling the carb if it's empty and there is no vacuum. If you don't know it's a vacuum operated tap and turn it to the middle position when you get off you are bound to get a flooded motor.

If the tap is playing up it can fail to close when the motor's stopped. It only needs a speck of rust under the vacuum operated needle and seat in the tap to make it stay open, then you've got three on positions and no off. They can also get a hole in the diaphragm that operates the tap. If the diaphragm has a hole fuel goes down the vacuum hose into the motor.

Lots of float needles leak a tiny amount, not enough to effect the running but enough to fill the sump with fuel when they sit for a while. The tap is the first and most important thing to get right. The manual taps can also develop leaks. There's a rubber washer in the manual tap with holes in it. On some models it's possible to flip the washer over so you are using the new unworn side. I'd make sure the tap was turning off completely before buying a new float needle..  It's easier just to pull the hose off and check there are no drips..

Edited January 27, 2023 by Mech

[Parham]

Mech...I knew you would try to help!  Thank you!  Here are some pics...I do not have the vacuum petcock.  Looks like someone might have replaced it already.  There is a short piece of hose on the carb that is plugged.  I assume (you know the acronym I bet...) that is where the petcock was connected.  There is also a piece of hose, disconnected, that disappears under the dashboard.  Probably the original petcock vacuum hose.  What are the positions on the petcock shown?

[Mech]

I don't know what those symbols on the carb mean..  Off will be horizontal though..

I don't recognise that carb from the hose layout, it's not the standard carb we get here, but I think that hose at the top center in the last photo would be a vacuum, either for the pump or the tap, and there is probably another vacuum port for the other, possibly that plugged one. It's usual to have a bigger hose going to the pump, and a smaller hose going to the tap. The two vacuum ports have fittings to suit.

In the first photo there's a hose opening upwards, that doesn't look  right.. if it's a breather it should be aiming down to keep crap out. And the fuel hose in that photo looks about ready to split where it goes on the carby.. If that was a standard suzuki carb that up facing hose would be a vacuum hose I think.

On the carbs around here, the left side of the carb has from front to back, a small vacuum hose fitting(pressed steel pipe) aiming up, then a larger vacuum hose fitting(machined brass) also aiming up, then the fuel at the rear(machined brass) also aiming up, and on the right rear there is a breather hose fitting facing down.

I'll have a look later and see if I have an old carb like that to check what the ports are..

[Parham]

Mech..I'm betting the positions on the petcock, based on the symbols, are up is "normal" (taller standpipe), down is "reserve" (shorter standpipe), and horizontal is "off". That "hose opening upwards" is not connected to the carb.  It disappears into the instrument panel and I can blow through it.  I think it's what was connected to the original petcock valve.

[Mech]

I'd doubt the hose goes to the instrument panel..  They have an engine and airbox venting hose that runs up under the range/rev/4wd panel where it branches and runs back down as two open breather hoses.. You might be blowing into one of them. I'd try and aim it downwards so it doesn't accumulate water or dirt.

I'd also change that fuel hose going onto the carb.. It looks like it's old or the wrong size and wall thickness.

[Gwbarm]

I don't recognize the carb either the hose with a screw in it looks like s fuel hose the other look like vacuum hose and the symbols on the petcock are strange it looks like open and closed, but im sure you have already figured it out.