Sat for too long. Bogs when twist throttle

[tmst08]

I posted this on the Yahoo board. But it's looking pretty dead, so I'm posting it here as well.

I went out today to fire up the FJ after she sat for a few months. I know - I'm
bad. I had put fuel stabilizer in to prevent the carbs from gumming up, but it
doesn't seem to have worked.

She starts up OK, but only with the choke pulled all the way out. The second I
push the choke back in or give her any throttle, she immediately dies. With
the choke pulled all the way out, she'll rev all the way to 6K or so. Twisting
the throttle at high RPMs causes the bog.

I'm reading around and it looks like maybe clogged pilot jet. But even after
rebuilding the carbs a few years ago, these terms still elude me.

One site I read recommends getting the RPMs high and then blocking the air
input and then letting it suddenly flow, as if this will force whatever is
stuck in the jet to break loose.

It seems to involve more than one jet, however. Could all of them be blocked?

I'm ready to pull the carbs but the throttle cable always gives me fits. So I'd just like to be sure it's necessary before proceeding down that path. Thanks for any help or suggestions of things I might try first.

-Tom
'92 FJ1200

[FJmonkey]

Tom, you are describing the classic plugged idle jets problem when sitting too long. Fuel stabilizer helps but only for so long with our Ethanol enhanced blends. I make sure I run the engine every 2 to 3 weeks to keep the fuel fresh and jets open. order a fresh set of bowl gaskets from RPM and pull the carbs. The idle jets are easy to get at once the carb bowls are off. Use a proper size screwdriver (or custom ground like I did) to avoid buggering up the soft material.

Once I was able to run carb cleaner and get the jets opened up. But the problem was not as pronounced and after about 3 tanks all was normal again. If the jets are fully clogged then the cleaner cannot flow past the gunk and dissolve it.

You have some really nice roads down your way, stay in touch for some scheduled SoCal rides.

[red]

Tmst08,

In the USA, my first choice of "carb cleaner" gas additives will be SeaFoam.  Most auto parts places will have it.  I'd siphon all of the old gas from the tank first, and start with a tank of fresh gas, mixed with some Seafoam.  Run the engine to fully warm, and then give the cleaner about a day or three to work it's magic.  Riding the bike while you wait will help.  You can burn the old gas from the bike in a car, which is okay because the big tank lets you mix in a lot of fresh gas.  Some SeaFoam in the car's gas tank won't hurt anything, either.

Cheers,
Red

[tmst08]

Thanks, all. It turned out to indeed be clogged pilot jets. I had forgotten how tiny is the bore on them. Shoving an ice pick through the openings was really tough.

Doing the job was made a little easier by having installed the Raforth kit during the recent (2K mi ago) rebuild. The insides were still pristine. BTW, if you know which jet is clogged, you could probably just drop the bowl to get it out, but only if you have the Raforth kit and no airbox. I would definitely try it. However, you might never know which jet, because to get the bike to start at all the choke must be on and then it runs on all 4 and there's no cold pipe.

I decided to replace the 112 with 110 main jets and put the stock airbox back in. So she's not as perky but quieter and a little more smooth and predictable.

Not riding much these days. Too much expense. Am probably going to look for a good home for her after hitting the canyons a few more times.

[Steve_in_Florida]

That nasty fuel residue is the bane of existence.

There was a discussion about Seafoam on one of the MG forums recently that I found quite interesting. An inquiring mind deduced from the Material Safety Data Sheets that Seafoam appears to be a combination of light oil, naptha, and isopropyl alcohol in the ratio of 4:2:1 .

RPM Randy has shared some "horror" pictures of carbs in past posts here, too.

FJ's should *NOT* be allowed to sit. Not at all.

At the very least, show them some love and start the engine periodically, just to keep the juices flowing.

Steve

[Steve_in_Florida]

There was a discussion about Seafoam on one of the MG forums recently that I found quite interesting. An inquiring mind deduced from the Material Safety Data Sheets that Seafoam appears to be a combination of light oil, naptha, and isopropyl alcohol in the ratio of 4:2:1 .

Here's the links to both the MG discussion and the experimenter's page (in case you care, or have too much time...) :

http://www.mgexp.com/phorum/read.php?1,3074603

http://hildstrom.com/projects/seafoam

Even a video:

https://youtu.be/WdT4DPFXIkM

True, the MG question was about carbon build-up in the cylinder, but the Seafoam product was mentioned, so I thought I'd share.

Draw your own conclusions. There is no "magic pill".

Steve