Missing Cylinders on Cold Start & Slow, Kicking Back on Very Hot Start

[HapHazard]

After cleaning my carbs (thanks to the excellent pictorial and text guides on this site ) on my 89 FJ1200, I'm experiencing a problem on cold start when using the choke, which seems to be getting worse.

On a cold startup, giving full choke, the engine will start on what sounds like 2 cylinders (#1 & #2, my estimate from touching the exhaust pipes), then #4 will come in intermittently, followed, with some in-and-out and popping, by #4. Then it runs great, after the choke is let off. Taking the choke off before all the cylinders come on line gives a low idle (with some cylinders not firing) and a stall. It started out going through this process in about 20 seconds, now it's like a minute and a half before it straightens out and runs on all cylinders.

Also, the last time I did the cold start, my tach stayed on "0" until #4 (I think) kicked in.

The only driveability problem I have when warm is an occasional very slightest momentary "hiccup" at about 1500 rpm under light throttle (I did not resynch the carbs after cleaning, and the idle mixture screws are set at 3 turns out). It is so slight and occasional, it doesn't bother me, I just mention it in case it matters regarding the startup situation.

During cleaning, I blew air and carb cleaner through the choke feed tube with the choke linkage held open, air and carb cleaner came out like crazy. I did not pull apart the choke plungers. Overall, I'd say I did a careful cleaning job (the second time ).

The next (probably unrelated situation) is if the engine is shut off after normal running on a very hot day, on restart, the engine cranks slowly, pings, cranks slowly, pings, cranks slowly... After releasing the starter button and waiting a few seconds, it will crank and start. My battery is a Westco, but a few years old. My voltages are 12.9 no load, 11.1 during cranking and 14.4 when running.

Does this suggest anything to anyone? Thanks for reading all this drivel, and any help is truly appreciated!

[SlowOldGuy]

If it's always the same cylinders that are slow to warm up then I think you may have missed cleaning the choke circuit fuel orifice on one or more carbs.

The orifice is in the float bowl, cast into the side of the bowl and down toward the bottom.  You will see a port in the bowl inside of which is a really tiny and very easily clogged orifice.  Since it's near the bottom of the bowl it gets the worst fuel crud when it dries out.   If the fuel orifice is clogged, the choke will usually make a cold start even worse since it's letting in lots more air without supplying the "desired" overly rich mixture for a cold start.

If your tach is not working while one or more cylinders is not firing, then you could have an electrical problem.  Could be intermittent coil or as simple as a corroded connector.  Check/clean the coil connectors under the front of the tank.

Next time it cranks slowly when hot, try cracking the throttle slightly when cranking and see if that helps.

Good luck and report any progress,
DavidR.

[Pat Conlon]

"......I did not resynch the carbs after cleaning... "

In addition to David'd advice, I would suggest syncing the carbs.
If you don't have access to the a set of carb sync. gauges, go ahead and buy one, it's money well spent.
Randy @ RPM has a good selection, with good prices.

[yamaha fj rider]

++1 David and Pat give good advise. If you don't have a carb sync buy one.

Kurt

[HapHazard]

Well, it seems to make sense - I didn't see where the choke is fed from inside the float bowl, so it would follow that it has some of that mineral-like crap that ethanol gasohol seems to enjoy making is probably plugging up the passage. Maybe I'll fit zippers onto the carbs this time! 

Thanks for the enlightenment!

[fj11.5]

the 89 here runs great, but popped and farted with the choke out, just checked the holes in the float bowls 1 was and still is blocked , even compressed air and a good soak in carb cleaner didn't budge it, so used a bowl that was good and all is well 

[HapHazard]

Well, it took me a while to get to it, but I pulled the carbs, and yes the "choke" fuel feed was plugged on two carbs.

They are NOT the easiest things to clean - it looks (as much as I can see down that tiny hole) like a brass jet in the bottom? I sprayed it with carb cleaner, and stabbed blindly into it with my thinnest guitar string, then blew lots of air through it.

It starts up now (yay!), but one of them might not be totally clean (it still pops a bit for a while).

I'd have taken some pictures of the bowls, but my camera was DATT (Dead At The Time). Thinking maybe some mention could be added to the carb cleaning file and illustrated carb post about cleaning the idle enrichment float bowl passage?

Thanks again everyone for solving my problem!