Help my 82 GS750 is flooding out and I can find the reason.

[Anonymous]

I had the same problem.

I kept having the same problem even after totaly rebuilding and dipping my carbs. It was not till I rebuilt the petcock that it stoped over flowing into the air box. Im glad I have rebuilt the carbs, and the petcock. If I had it to do over I would have done all that from the start. I bet I had the carbs off 7 or 8 times. I was intimidated by the thought of not being able to figure out how to get the carbs back together. Once I took a salvage set appart though I realized how simple it is. The salvage set helped me alot in figuring out how to do mine without breaking anything. + when I did break a float stem I was able to rob one off of the junk set and drill and tap it on with a screw.

The next time I get into another older bike I will do the carbs, petcock, and intake boot O rings all from the start.

[lhanscom]

The o-ring wraps around the needle valve and they dry out and shrink with age. You can also shave off a bit off it reinstalling them if they are not oiled. You can easily have fuel seeping around them.

My carbs have been overflowing while the bike has been sitting, and I know the petcock was faulty, and have hopefully fixed. However, in order to get the carbs to overflow something has to be wrong with the carbs too, I think mine may have the o-ring problem, but have no idea where to get a replacement. Do you have to get the whole assembly, or can you just replace the o-ring? Also, now that the petcock is fixed, is it even an issue having the o-ring seep a little? I would think it would be a small enough amount so that the engine at idle would burn enough gas so it wouldn't matter. Is that true? Thanks.

[moto_dan]

The o-ring wraps around the needle valve and they dry out and shrink with age. You can also shave off a bit off it reinstalling them if they are not oiled. You can easily have fuel seeping around them.

My carbs have been overflowing while the bike has been sitting, and I know the petcock was faulty, and have hopefully fixed. However, in order to get the carbs to overflow something has to be wrong with the carbs too, I think mine may have the o-ring problem, but have no idea where to get a replacement. Do you have to get the whole assembly, or can you just replace the o-ring? Also, now that the petcock is fixed, is it even an issue having the o-ring seep a little? I would think it would be a small enough amount so that the engine at idle would burn enough gas so it wouldn't matter. Is that true? Thanks.

robert barr has o-ring sets very reasonable at http://home.att.net/~robert.barr/ Slight seeping while engine is running would probably not be a major concern. Others may provide further info.

[Anonymous]

Also, now that the petcock is fixed, is it even an issue having the o-ring seep a little? I would think it would be a small enough amount so that the engine at idle would burn enough gas so it wouldn't matter. Is that true?

I replaced my petcock, but did nothing further pending a more pressing need to pull the carbs apart. The carbs had been professionally cleaned (by someone I really trust) and necessary o-rings replaced soon before the petcock failed. Even so, it was clear that some seepage was occurring when the petcock went bad. As you stated, any one idling cylinder surely uses more fuel than the one drop each 45 seconds that flowed from my airbox (engine off) before the new petcock. I can't imagine that something as volatile as gasoline wouldn't seep to some small extent at the best of times given the imperfect conditions that the needles and seats are exposed to.
Even supposing that the entire contents of the shortish fuel line downstream from the petcock were to find its way into my crankcase on each cooldown, my recent reading about aircraft engines leads me to believe this wouldn't be the end of the world ('plane engine crankcases are routinely fed raw fuel to thin the oil at startup, even in warmish climates - the fuel boils off through the engine breather as the engine warms).
Finally, moto_dan provided a link earlier in this posting-string for new o-rings (I've got my new set handy in case the carbs have to come apart). I regularly see new pattern-parts needle/seat/o-ring sets for Suzuki on Ebay at popular prices, but I don't know what is available for your model.

[Anonymous]

Carb Flooding

I've read all the replies posted so far and all seem good advice to me. The only thing I would like to add is that when this happened on my 1977 GS750 the culprit was Rust coming from the petrol tank. I tried cleaning everything but the final solution was to get the tank overhauled Inside and Outside -- since then all is OK

[earlfor]

I bypassed all the fuel seepage, faulty petcock diaphram, vacum leak in the fuel system problems a long time ago. :-) I replaced the stock fuel petcock with a Pingel petcock. It has three positions, off, reserve and on.
There is no vacum line. The rule I have for myself is the engine cannot be shut down if the petcock is turned on. Turn off fuel, turn ignition off. No leaks or seepage possible.

Earl

[argonsagas]

Maybe old age is making me a bit denser than before, but what I read is that your #3 and 4 bowls are full of fuel, and #3 and 4 plugs are wet/dark, but #1 and 2 fuel bowls are dry and plugs are light in colour.

The carb bowls cannot possibly be dry if there is any fuel flowing to them, so I must assume there is a fuel blockage and cylinders 1 and 2 have no fuel to run on, while 3 and 4 are running rich, and overflowing, because the floats are set too high, or they are defective. Or both.

There is a fuel delivery tube that runs between the carbs, and the above makes it look like your delivery tube is blocked immediately beside the inlet point from the tank, so that no fuel at all is reaching carbs 1 and 2.

Blockage of that tube requires a significant amount of junk, so you must have had a great deal of it in your system.

You seem to be in dire need of a major cleaning and set-up, but you may have only attended to part of the job up to now.

I would suggest you go back to the carb cleaning section on the Forum and follow it completely from point one through to the last. You may have done so already, but it looks like one or more shortcuts were taken...(steps missed or bypassed) and the cost of taking the shortcuts is having to do the entire job again......properly

[Anonymous]

Flooding GS750

I had a day off so I took the carbs off again and had them cleaned and am waiting for the new O-rings before I put them back together.I was told by the shop that the carbs looked great and the flooding problem wasnt in the carbs.I noticed a small amount of rust colored gas in the carbs when I removed them so I have the tank off right now treating it.The treatment kit comes with a solution that you coat the tank with after all rust is removed,I have heard war stories about that stuff comming off and really messing up your carbs.Should I ignore those warnings or should I not apply the coating.I hope that my problem all along was a dirty tank that I thought was clean enough.Should I rebuild the petcock anyway even though in the ON position it only flows gas if there is a vacume?It does seem to be working properly.I have worked on this thing so much lately that iam burned out so if treating the tank doesnt stop the flooding than Ill probably just park it in the shed and wait until spring to put it in the shop.Once again I appreciate all the help/advice that I recieved from this web site and its members.THANKS TO EVERYONE!!!! By the end of next week I should have the O-rings in and have it all back together,Ill let everyone know then if the problem is solved or not.

[Billy Ricks]

Check out Sudco. They have a website. One of their products is a tank treatment that knocks out the rust and treats it in one step.

[argonsagas]

If you have flooding, it is ALWAYS a carb problem, simply because there is no other way for the fuel to reach the engine, except by fuel tank/line leaks.

Depending on float setting, you can induce flooding while the bike is on the side stand, as keeping the bike off vertical changes the fuel surface angle in the bowl, and this can affect the float action.

If you have found rust in the bowls, you likely have identified your problem of floding as rust particles do not allow the needle to properly fit the seat and/or o-rings, thus allowing fuel to flow.

I, too, have heard and read different stories about coating the tank. Some people have good luck, some don't.

One thing is certain, though, and that is you have to be extremely careful with the chemicals and their fumes.

They cover all the bases, being corrosive, toxic / poisonous, and flammable.

You must have full ventilation and you should be out doors when using it, but note that the stuff is temperature-sensitive, so if it is cold where you are, you will have to wait a while for warmer weather.

I found a shop that specializes in gas tanks and had them do it....cost for Kreem was $40. plus $6. taxes, and having it done professionally was $90. including taxes. I also got a two year guarantee, in writing.

Some radiator shops do the same work.

[Anonymous]

I did the Kreem and would do it again.

I did the Kreem on mine, and would do it again in the future. If you are good at figuring out how the use chemicals without endangering yourself + making a mess of things you should do fine. My tank is so clean and white inside sometimes I cant even see the gas. The trick is rinsing all the rust out. Other wise it will end up in the coating on the final step. A sponge on a stick and flooding the tank out repeatedly did the trick. I also used a cold air blower to vent the tank and set up the Kreem. I only needed about 3/4 of the bottle to do my tank.

[Anonymous]

Re: Flooding GS750

Should I rebuild the petcock anyway even though in the ON position it only flows gas if there is a vacume?It does seem to be working properly.

Remember that there are two common problems caused by a faulty petcock. You have to consider and test for both problems:

1. As you suggest, the petcock can flow fuel without a vacuum.

2. The vacuum diaphram itself can be torn.

A torn vacuum diaphram allows fuel to be pulled into the engine through the vacuum hose when the engine creates vacuum. This causes rough running because the cylinder with the vacuum take-off runs too rich (raw, unatomized fuel).

The other symptom is a slow leak of fuel through that vacuum line when the engine is off. This is usually marked by a slowly growing puddle of fuel under the bike as it sits overnight. In my case, the fuel flowed from the drain hose from the airbox. Fuel can also find its way into the cylinder and then past the rings into the crankcase.

Here is how to test for both problems:

1. With the engine off and the petcock in the "run (on?)" position, pull the fuel line. Does fuel flow from the petcock? Let stand a long time when checking. There should be no flow. Repeat this test with the petcock in the "res" position if present.

Now move the selector to prime. *** Warning - Expect Fuel to Flow! *** Fuel should flow on "pri". Then, turn to "run (on?)" to stop the flow.

2. Leave the fuel line off. Pull the vacuum line off at the engine, not the petcock end. With the petcock on "run (on?)" or "res", apply vacuum to the vacuum line (by mouth should work *** don't inhale or swallow fuel that may be present in the line***). While vacuum is applied fuel should flow, and should stop entirely just as soon as you stop applying vacuum.

You should have found no gas in the vacuum line. If you got a mouthful of gas while applying vacuum, you can be certain your petcock is bad.

If no problem was apparent after this testing, I would thoroughly pinch off that vacuum line (it must be connected or you'll have a terrible lean condition on cylinder two) and try running the bike on "pri". If it runs better, suspect that petcock.

Ron and others are correct in stating that you have to deal with any rust/dirt condition in your tank/lines/carbs first. And, if you have a laundry list of problems going on, you're going to have a hard time diagnosing the problems yourself. Do the best job you can, eliminating the potential problems one at a time. 1. Rust/dirt 2. Install Inline Fuel Filter 3. Petcock 4. Rubber Intake Boots 5. Fine points inside the carbs. Good luck.

Is there anything I got wrong here, guys?

[Anonymous]

flooding out 750

Over the weekend I used the KREEM to first clean the tank then coat the tank and let me tell you that there was alot of rust in the tank that I couldnt see before.It looks really good now and all Iam waiting on is the O-rings to come in so I can put it back together and see if the flooding problem is fixed or not.Weve had cld weather here for 2 mths. and the past 2 days its been 65 degrees,perfect for riding and MY MOTORCYCLE IS NOT RUNNING!!!! Its suppose to turn cold again this week,it figures! Somehow I messed up and erased my original topic but all the replys are still here ther just under (How fast will my 750 run).Iam still not exactly clear on the float setting so if anyone out there can explaine that to me again I would really be thankfull.