Choke left on = hydrolocked engine

[jfman]

Hello guys,

 

I ran my 1988 venture on choke for a good 20 minutes as I am trying diagnose a carb issue.

 

Anyway I shut the bike off(with the choke pulled)walked away for a good 5-10 minutes and when I can back the bike would not turn over, hydrolocked in fuel.

 

Now I know I should not leave the choke/enrichner pulled on a resting motorcycle but is this normal for the bike to fill with fuel this quickly?

 

Doesnt the enrichner need a vaccum to draw fuel?

 

What do you guyz think?

[CaseyJ955]

It's on an elec fuel pump, it should not have gravity fed any notable amount of fuel into the engine just sitting with the choke pulled and the key off. I've had badly flooded engines on older bikes by forgetting to turn the valve off (gravity feed) but never had or heard of one actually hydrolocking this way. Choke on/engine and key off should have no real effect while it sits. If it were dumping enough fuel to hydrolock then it should have been barely ridable, if at all.

 

DO NOT keep trying start it if you suspect a hydrolock condition, get the plugs out (kill ign and fuel circuits, and push her outside where nothing can ignite the faw fuel spraying out) and give it a few spins to clear the cyls. Hopefuly this will give you an opportunity to see where the extra fuel is coming from. If you try hard enough to start a hydrolocked engine you can start bending rods.

 

Flooding and rich running is not unusual for an older machine with decades old CV carbs.

 

When you first turn on the key, before starting, you should hear the fuel pump for a couple seconds then it should stop, is that what you hear?

 

Do you ever smell raw fuel when it sits? When riding?

 

Battery fully charged?

 

What symptom were you diagnosing with the choke?

[videoarizona]

 

There is no way for the enrichning circuit to dump fuel. And with the tank below the carbs, no way the fuel from the tank can do that either.

My feeling is you had a carb dump it's bowl after you shut her off. Stuck float.

[jfman]

Quite simply the bike has been sitting for over 4 years and I just bought it for 250$

 

The fuel pump does work.

 

Also gravity may have a play here because I am using a funnel set up higher than the carbs to feed the line with fresh fuel. I pulled the line at the petcock and I am running a long fuel line to a funnel tied to the topcase.

 

It only runs on choke and wont idle without it or barely. I was trying to unclog the pilot circuits w/o pulling the carbs but at this point I think I have to remove the carbs if there is a risk that I have a stuck float.

Edited November 25, 2019 by jfman

[OutKast]

Quite simply the bike has been sitting for over 4 years and I just bought it for 250$

 

The fuel pump does work.

 

Also gravity may have a play here because I am using a funnel set up higher than the carbs to feed the line with fresh fuel. I pulled the line at the petcock and I am running a long fuel line to a funnel tied to the topcase.

 

It only runs on choke and wont idle without it or barely. I was trying to unclog the pilot circuits w/o pulling the carbs but at this point I think I have to remove the carbs if there is a risk that I have a stuck float.

 

Under this condition, a stuck float or needle valve would let the fuel above the carb level to fill a cylinder. You are correct, the choke (carb enrichener) can only pass fuel under vacuum (engine running or at least cranking). If it runs only on choke, you have idle jets plugged with dried up old fuel varnish. If they flow any at all, Seafoam or similar may clean them up, but if completely clogged will probably require bowl removal and cleaning.

[saddlebum]

Under this condition, a stuck float or needle valve would let the fuel above the carb level to fill a cylinder. You are correct, the choke (carb enrichener) can only pass fuel under vacuum (engine running or at least cranking). If it runs only on choke, you have idle jets plugged with dried up old fuel varnish. If they flow any at all, Seafoam or similar may clean them up, but if completely clogged will probably require bowl removal and cleaning.

Stuck open needle seats can cause this but if the floats are stuck down and needle seats open then you should see fuel on the ground from the float bowl overflow/vent hoses. As stated earlier pull the plugs and crank the engne to eliminate fuel from the cylinders. You can try filling the float bowels with a concentrated mixture of seafoam and gas or good carb cleaner spray and then let it sit overnight then tap the carbs gently to attempt to dislodge the stick floats. Crank the engine again to remove any fuel leaked into the engine and it may be a good idea to replace your engine oil as well in case enough fuel leaked in and past the rings to dilute the engine oil. When cranking the engine over W/O the plugs in disable the ignition or ground the plug wires to the block. After that install your plugs and see if it will fire up. Again while idling if it fires up watch for fuel dripping on the ground in the kick stand area. This will indicate floats still not functioning properly and you will likely have to remove the carbs for some O/H work. BTW there is one drain tube for each carb and the run down past the pivot point of the double kick stand.

[jfman]

Thanks a lot guyz.

 

I think I am reaching the point where it's worth it to pull the carbs because I am wasting too much time trying to fix it without a proper cleaning.

Edited November 26, 2019 by jfman

[MiCarl]

 

I think I am reaching the point where it's worth it to pull the carbs because I am wasting too much time trying to fix it without a proper cleaning.

 

Yep. Time do do the job right.

[saddlebum]

When it's time to set your floats the yamaha method is a real pain. But, you can dry set them before you put the bowels back on, by the methods/tips here https://www.venturerider.org/forum/showthread.php?66468-Float-levels or as I prefer you can wet set them on the bench.

 

I devised this setup https://www.venturerider.org/forum/showthread.php?86821-home-made-set-up-for-wet-setting-floats-on-the-bench to wet set them and it worked a treat. A bicycle pump works great to pressurize the cylinder. Make sure sure the pressure you add to the cylinder equals your fuel pumps delivery pressure. If you do use the shop compressor I recommend you shut it off 1st and drain the tank down to about 10 or 20 psi so you have better control of the air going into the rigged up fuel cell.

 

When it comes time to reassemble the four carbs together I found a cut piece of scrap polished granite makes a great flat base to set the carbs on when you are tightening the brackets which hold the carbs together so they will sit nice and flat when you put them back on the bike. A lot of times you can get a srap piece of cut out material from the granite counter top installers for nothing.

[jfman]

When it's time to set your floats the yamaha method is a real pain. But, you can dry set them before you put the bowels back on, by the methods/tips here https://www.venturerider.org/forum/showthread.php?66468-Float-levels or as I prefer you can wet set them on the bench.

 

I devised this setup https://www.venturerider.org/forum/showthread.php?86821-home-made-set-up-for-wet-setting-floats-on-the-bench to wet set them and it worked a treat. A bicycle pump works great to pressurize the cylinder. Make sure sure the pressure you add to the cylinder equals your fuel pumps delivery pressure. If you do use the shop compressor I recommend you shut it off 1st and drain the tank down to about 10 or 20 psi so you have better control of the air going into the rigged up fuel cell.

 

When it comes time to reassemble the four carbs together I found a cut piece of scrap polished granite makes a great flat base to set the carbs on when you are tightening the brackets which hold the carbs together so they will sit nice and flat when you put them back on the bike. A lot of times you can get a srap piece of cut out material from the granite counter top installers for nothing.

 

The the floats go out of spec because the of the wear on the float needle and seat?

[cowpuc]

The the floats go out of spec because the of the wear on the float needle and seat?

 

Sure.. Also when you replace the needle and/or seat with new the float height should be checked as a tiny little bit of difference in the new parts dimensions can raise float level too.. It's always best to check the float height anytime you button up a carb bowl even if you just opened it to clean jets... Better to know than wonder