Quadrunner not starting, gas in oil.

[Blue Sapphire]

1997 Quadrunner LT-4WD. 

Symptoms:
Became more and more difficult to start. Eventually wouldn't start unless pulled; showed symptoms of bad starter.
While replacing starter motor, I noticed that the oil window was full. There was nothing wrong with the starter motor in the first place.

History:
My Father-in-law moved to Florida, so he left me with this beast. When I first started with it, it was a dumpster-bound immovable mess, locked wheel drums and all. I really poured some labor onto it, and he was tickled pink to ride it around when he came back up to visit.

Here's what I did to get it running: 
Carburetor was cleaned and updated using a repair kit. At first, many of the mysterious vacuum lines running to the carb were either blocked off or not even attached. After hours of head-scratching, I finally found a configuration that had it running. I am still not 100% certain that these vacuum lines are routed ideally. Vacuum petcock was replaced, but I suspect the new one may have been incorrectly assembled from the factory. I do not fully understand the settings/markings on this petcock (PRI), so I can't rule it out as a problem.

Until recently, the quad ran and idled well for the most part. There's one bug I wasn't able to work out, which I should also mention. The quad will stall out at high speed when in high gear, for example, while given full gas on a straight road. Since this machine is mostly just a work horse that's used at slow speeds, I didn't chase the problem, but I mention it in case it's related. 

At this point, I'm a bit lost. The oil has been drained, and I'm just about to go remove the carb to look for a bad float. This seems like the most probable culprit to me. If it's any other carb problem, I probably won't be able to tell or identify it, so I'd like to hear some thoughts. Please consider that I have very limited experience with machines like this. I'm not afraid to tinker, but a problem of this complexity is on the overwhelming side for me, so I'd really like some troubleshooting advice. I'll also appreciate it if you keep it simple.

Just so that I'm going in the right direction, where should I be looking first? How do I troubleshoot this carb? If it's not the carburetor at all, what else could it be?
Thanks in advance. 
 

[davefrombc]

From what you describe, I  would guess it's your routing of  "vacuum"  lines. You have likely connected the crankcase vent line to a fuel drain or possibly a "PRImer" line on the carb..  Only  guesses because I am not familiar with your Quadrunner.  There  should be a relevant service manual in the downloads section.. You need either a paid membership OR  10  posts in the forum to  download the manuals.

Here  is the link to  download it. I hope   you get it running well, Let us  know when you get it sorted out .  Every solved problem  is a help to those following who  may have the same or similar trouble.

The snow is retreating and trails are opening up in the north.. Sometimes we envy  Florida's endless summer,  but when we follow the news, that's about all we envy  about "The Flower" state at this time .

 

[Blue Sapphire]

Thanks @ davefrombc. I'm already in possession of the service manual, so I'll take a look to see if I've...

19 minutes ago, davefrombc said:

connected the crankcase vent line to a fuel drain or possibly a "PRImer" line on the carb.. 

But also note that this quad has been running pretty well over the last two years since cleaning the carb, so I'm hesitant to believe that I totally botched a line. I'm open to being wrong, though!
 

[davefrombc]

Ok..  That was the only thing I could think  of when you said you'd worked on the carb and had  gas in the crankcase. I  know of it being done before  so  as I said ,  I  could only suggest the possibility with the info  I  had .. When  you find the problem  please let us know..  Take care and  happy riding .  I'm  wondering since the carb has been fine since you worked on it If the  drain  line  was connected to the crankcase , the float may have stuck  and flooded  allowing the drain  line to  run the overflow to the crankcase.  Just   curious musing on my  part .

 

Edited April 25, 2022 by davefrombc

[Mech]

The fuel pump may have a hole in it's diaphragm allowing fuel down the pump's vacuum hose..

You can check by sniffing or sucking very carefully on the pump's vacuum hose.. if it's got fuel in it then the diaphragm's holed.

And I think the fuel tap you have doesn't have an "off" position. If it's got a "Pri" position, that stands for prime, and it's because both other positions, main and reserve, are both turned off automatically when the vacuum's not being applied to a diaphragm on the back of the tap. If there's no vacuum being applied then the Pri position allows fuel to flow, which is handy if the fuel has run out and the carby is empty.  If your bike doesn't have a vacuum hose to the back of the fuel tap, then you have probably been running it on Pri, and the diaphragm operated positions have both been off positions for you. Perhaps the diaphragm in the fuel tap has got a hole in it now.

 

 

[Blue Sapphire]

On 4/26/2022 at 5:39 PM, Mech said:

 

Thanks for that reply. Useful info. Lots to take in.

It's nice to know that the "PRI" setting can be useful after maintenance; I had quite a time getting it to start the last time the carb was emptied.

Still working on the problem in my spare time. No progress yet.