Kawasaki FD620D running poorly. Help?!

[Rock Doctor]

Sorry, all I'm doing there is turning the engine over by hand, the screwdriver is touching the top of the piston. When the screwdriver stops moving, I know the piston is at TDC (Top Dead Center)

Seafoam will work fine. Another option is to add a little ATF to your fuel. Automatic Transmition Fluid, 1/4 to 1/2 liter to a tank.
The valves will only start acting up if you run old fuel or have water In your gas.

RD

[fmints]

Sorry, all I'm doing there is turning the engine over by hand, the screwdriver is touching the top of the piston. When the screwdriver stops moving, I know the piston is at TDC (Top Dead Center)

To caveat what RD said: When the screwdriver stops moving up, the piston is at top dead center. Also, you have to check both the exhaust and intake valve's lash, so you have to move the piston twice to set the other valve. So move one valve to TDC and check the lash and then move the other valve to TDC and check the lash. Then go to the other side and do the other piston. I've learned this procedure from this dude, Lawn Mower Repair Valve Adjustment Briggs and Stratton V-Twin - YouTube, when I was having starting, loss of power and backfiring problems with my 16hp V-Twin Briggs. Each engine model has specific measurement settings for the lash, which I think that RD has you covered on that.

Regular oil changes keeps my valves from sticking, but remedies like the ATF, and seafoam works well. Seafoam is used in the oil a few hours of use prior to the oil change, every 100 hours or at the end or beginning of season (once a year) and running Seafoam in your fuel tank every 5 tank refills or when storing the machine for a long while. Really any fuel stabilizer will work, but I prefer Seafoam.

Fred

[Rock Doctor]

Fred, please correct me if I'm wrong here. I have it even thought about this In a while.
On the Kawi, don't you bring the piston to TDC on the Compression Stroke, and then check/set both the intake and exhaust valves?

RD

[Rock Doctor]

Ya, it was bugging me so I went and checked.
Bring one piston to TDC on the Compression Stroke, check/set both valves, then move on to the second cylinder and repeat.


RD

[plott hound]

yupper,compression stroke is what you want to set the valves.remember to also to this when engine is cold.if the valves are real sticky forget about the snake oil additives.my luck is really bad and this stuff never works for me.pull the heads and do a valve job,then you can physically clean all the gunk off the valve train.its a real nice easy project if the valves are not burnt or the guides are not wore out.

http://www.6x6world.com/forums/argo-atvs/21518-pulled-trigger-conquest-7.html

[fmints]

Fred, please correct me if I'm wrong here. I have it even thought about this In a while.
On the Kawi, don't you bring the piston to TDC on the Compression Stroke, and then check/set both the intake and exhaust valves?

RD

The book probably states that for the Kawi, and I mostly work on Briggs, but valve lash is pretty much valve lash. As for doing both intake and exhaust at the same TDC, you wont be able to because one valve is going to be super loose and the other is going to be super tight. Then when you do the other side and then recheck all of your measurements, you will still be out of adjustment. Each push rod has to have the same clearance. If not then one will stay open too long or not open long enough, (your typical backfiring, stuttering, hard to start, loss of power symptons). I always do one valve at a time bringing that one valve to TDC and make adjustments, and after I do all four valves, I go back and recheck each one. Once I made adjustments, I recheck the valves when I service the machine, or sometimes for S$*# and giggles.

Cbass's Bandolera was acting up last April at Busco, lossing power and backfiring something fierce. After about 2 hours of head rubbing and the usual "What about this and what about that?", a 30 minute Valve lash adjustment had him back in the game, and with a more responsive throttle and with more power and torque. I haven't been doing this all of my life, just over the past few years, and this procedure has worked on all engines that I have rebuilt or tinkered with be it ATV or Motorcycle.

But then again, Kawi maybe different than the Briggs. I guess you should always follow the book.

[Rock Doctor]

As for doing both intake and exhaust at the same TDC, you wont be able to because one valve is going to be super loose and the other is going to be super tight.

But then again, Kawi maybe different than the Briggs. I guess you should always follow the book.

I know little to nothing about Briggs, so I'm going to have to assume your last line is correct, lol.

As for doing both valves at the same time............. If your Piston is at TDC on the Compression Stroke, BOTH the Intake and Exhaust valves are fully closed and the Rocker Arms are loose. At the 2:00 mark in my vid, you can see me wiggle both Rocker Arms at the same time. I guess little differences in engines can make big differences in maint procedures, lol.

RD

[JohnF]

The carburetor has two main circuits: idle and high idle. If you look along the back of the barrel you'll see few tiny holes that align with the bottom of the butterfly valve. This is how the carb makes the switch between circuits. If your idle circuit where clear and your high idle circuit plugged then the carburetor wouldn't make the switch and would act just as you've described.

[gimmegreens336]

Saturday night: I went out to do the valve job and gap my plugs. I was hoping it could limp into the shop but that didn't happen. I had to do a bush repair by cell phone light. I didn't have service to check the site and didn't know what TDC was. I had Spookum's phone number but I replaced my phone and didn't have anyone to reach out to. Anyway, I pulled the valve covers off for inspection. Everything seemed to be correct. Rods in place, when I spun the primary clutch they went through their motions.

Yesterday: Went back out during daylight after reading the comments. Still no luck for finding TDC. I can find what I assume is TDC but I have no proof. I don't know what the flywheel is for me to look for marks. Everything down there is covered in a layer of dried mud anyway, hard to identify marks or writing. I can stick long skinny screwdrivers down by the rods but I cannot identify a "piston." There was a potential "piston" that moved the screwdriver a LITTLE BIT while rotating the clutch but it probably only moved a half inch up and down, how much movement is in the said piston? I can spin the primary clutch until both rocker arms are loose, both valves are up. I checked the lash at this point and it was approx .014-.016. I adjusted the front set to .010 and didn't mess with the back set. I may have adjusted them at some point different than TDC so I didn't proceed incase I have to go back and re-adjust them.

Front side valves:

Back side valves:

Back side valve cover, a random washer on the top right bolt? (No other bolt on the valve covers had washers on them) I guess I removed the wire before I snapped the pic but there was a ground? wire on the bottom right bolt too.



After the covers were buttoned up and the plugs were gapped I tried to start her.

She will run in full choke only. Will not run un-choked, will not run when revved (choked or un-choked).

Checked the fuel flow, looked like there was a lot of air in the fuel coming out of the line by the carb. Removed the in-line filter by the carb and that took the air out of the flow.

Still won't run except in full choke with no throttle.

Took the carb back off and that's where we're at now. I took it apart and cleaned it again.

Actually let me ask this: Could this be a float problem? When I take the carb off and drain the fuel from the bowl before disassembly, I use the fuel drain screw to drain it. I bet there is only around 1 oz of fuel that comes out when I drain it before disassembly. Should there be more fuel that drains out? Is my bowl not filling properly? I've seen a few threads on here about this particular carb and the float assembly failing.

Let me know what yall think!

Thanks for all the help!

[fmints]

Ok, TDC is when the piston is at its most highest point inside the cylinder. you can get the piston to TDC (Top Dead Center) by placing a screwdriver carefully inside of the sparkplug hole,, then rotate the clutch (which is rotating the flywheel, and crank) until the piston is at it's most highest point, by looking at the screwdriver. when you do this, one of the valves will be loose and the other one would tight. Adjust the one with the biggest gap to whatever the manual says. then rotate the clutch again until the screwdriver goes down an back up again. When this happens you will adjust the other valve. after you have adjusted it, rotate the clutch again to check the first valve, then rotate and check the second valve again. It should all measure out good. Then go to the other side of the engine and do the same procedure again.

I wouldn't mess with the carb at all until you have the valves dialed in, and trace I would trace the ground to find the source and then put it back. Im going to PM you my number incase you need help.

[JohnF]

... Actually let me ask this: Could this be a float problem? ...

Yes.

Do you have the service manual? Page 2-8 describes how the carburetor works.

2-13 describes float adjustment.

Ok, so lets do a little troubleshooting.
If the float was stuck closed then it wouldn't run at all. Yours is running at low idle.
If the float didn't open enough to allow a fuel rate enough for high idle then it would probably reach high idle and then surge. Unless it was really bad, then it would die.
The float level affects the "accelerator pump" function of the carburetor. This functions is accomplished via an immersion tube (huh, the parts blowup in the manual above calls it an Emarsion Tube???) that sits in a reservoir. When call for, the fuel is sucked out of this reservoir. As the level drops it un-ports air holes in the tube effectively increasing air. What is trying to happen here is when you open the throttle the air flow can accelerate faster than the fuel which is heavier so the carb meters a bunch more fuel at this change over. The important part (sigh) is that the reservoir level is the same as the float level. If the level is too low, then the air/fuel gets too lean and the engine dies. If this is the case, you should be able to creep slowly to high idle.

As a side note, the main jet is in the bottom of the float bowl. If the float is set too low the engine will run fine on the level but die when the jet un-ports. Probably pointed downhill or port side high. That's really a function of the float bowl geometry in the design but a too low float adjustment screws that up.

I'm still thinking bypass holes are plugged. Second guess is fuel pump or float valve not allowing enough fuel flow through.

And for draining I usually unplug the fuel pump and let the engine run it mostly dry.

... one of the valves will be loose and the other one would tight. ...

Wouldn't both be loose at TDC of the compression stroke? I think RD is suggesting TDC of the compression stroke for this reason.

[Edit] shoot, I see there was a bit of conversation about the above. I just went back to catch up. Sorry for bring it up again, it's just that I think for any 4-cycle engine there has to be a TDC where both are loose (compression stroke) and this is what prompted my comment.

[eddieb1965]

You need to find out what the problem really is.I would start engine and dribble some gas directly into the throat of the carb and apply some throttle to see if it revs up.That will tell you if it is carb or fuel pump related.I havent saw an engine do what you are describing by having improper valve adjustment.If it is fuel related,I would start by taking off the gas cap (make sure system is vented),change fuel filter (again)and make sure the line has no pinches or pinholes.blow back up the fuel line into the tank(I have seen plastic shavings where they drill the tank block fuel port in bottom of tank.Lastly have someone crank engine with line off the carb and into a bottle and see if it is pumping fuel or enough fuel.

[gimmegreens336]

Thanks so much to everyone.

I am going to re-install the carb tonight and see if I have similar symptoms (full choke, low idle only). If I have the same problems I will uninstall the carb again and take pictures of everything I'm doing. I set the float according to the manual but some of the language is spanish to me. I believe I did exactly as the manual says but if I can't get her to run this evening I am going to start from scratch with pictures on here to confirm I'm doing it correctly.


I'm with you Eddie, I don't think improper valve adjustment is my problem but I'm happy to adjust them for the learning experience. Also I'm glad I took the covers off just to rule out a rod out from under a rocker arm. I am def getting good flow from the pump, that's confirmed.. When the motor wouldn't turn over at all, not with choke or anything, I could pour some fuel into the carb throat and it would sputter like it wanted to start but not fully get to idling. It's so sporadic, one day it wants to start and idle, the next day it doesn't even want to idle. The best I know right now is that it will idle in full choke only. (Adjusting idle-mix screw doesn't make a significant difference, even when opened 3-4 full turns)

Gotta go, will check back.

Thanks yall

[gimmegreens336]

I don't think there is a sufficient alternative to blowing out the carb.

I stripped her down last night and soaked her in carb cleaner again. I use that big can with the basket in it. After rinsing with clean water I still noticed some gummy stuff in there. I don't have an air compressor so I bought some compressed canned air and blew her out. WOW - big difference. Pin sized holes that I did not know existed were clearing out everywhere.

So I put her back on there, noticed that the gasket between the carb and top end ripped. I just bought the gasket last week and it was a metal gasket, was surprised to see it ripped already. Gotta replace that.

So I began tuning. She idled and revved smooth as hell. It was noticeably quieter from the front valves that were adjusted and I can tell the rear ones need to be adjusted, based on the little "pings" that I hear coming from that side. Dialed back the fuel mix as it was bogging down with too much gas, presumably from the better carb cleaning. She was revving and idling so smooth, better than she's ever sounded.

So we decided to take a ride.

I took her up and down the street and around the house with no problem. More power than ever.

Then she died. lol

I am seeing a reoccurring theme here. Seems like every time I get her running like a top, she only does so for a few minutes, then dies. When she dies I cannot get her started again immediately. I don't know if she'll start back in an hour or two, but she won't start in the first 20 or so minutes after dying. I truly don't think it's a fuel problem anymore. Clean gas, clean tank, new filter, new fuel line, good flow from pump, clean carburetor - and she runs like a DREAM before shutting down.

I took videos but I think they're useless. They were took while tuning, all it shows is the machine running well.

Now - I don't even know what a "coil" is. I do vaguely remember reading threads about a bad coil and not operating when hot. Is this right? What else could cause the symptoms described? Scratch the symptoms described before this post, I believe I had done a sh***y job of cleaning the carburetor. The new problem is that it will run for 10 minutes before shutting down then I can't get her re-started. (The temp gauge shows nothing abnormal)

Thanks again in advance!

[JohnF]

Cool! Down to only one zillion things that can be wrong.

So, when it won't start, put it into neutral, pull a spark plug wire and hold your thumb on the end ... okay, just kidding on holding the thumb on the end - lay the wire next to the engine block, and have a helper crank it a bit for you. Check for spark. Works great at night.

Try to taking the gas cap off - could be that your tank vent is plugged. [edit] Do this when it dies and see if it suddenly gets better. Do this one first. It's really easy and doesn't require opening the hood. I'm voting this most likely of the things that I know.

I've heard of folks having intermittent problems with stuff floating around in the tank that plugs the fuel pickup for short periods.