Help identifying Hitachi carb EA81

steptoe · Post by **steptoe** » Mon Sep 02, 2013 7:34 am

Look at the lucky buggers location..... did cars even come with a choke up there !! An option box ??

Back in the day, places like Christmas Island had Mercedes delivered without heaters!

David D · Post by **David D** » Mon Sep 02, 2013 7:52 am

Thanks, Tambox. The choke is a manual one with the auto shut off - when it warms up it pops back in. When the car is running, the revs increase when I pull the choke out so this may not be the issue but I'll definitely check it. Could it still need an adjustment though? I'll read up on it.
Strangely, the car started fine yesterday morning and this morning but that does happen - it's not a problem every single time I start it.

Steptoe, someone at work did say I shouldn't need a choke up here but it has always needed it in the mornings. Does get a bit chilly in the winter but nothing compared to what I'm used to - I'm from England originally! There was a VicRoads rego renewal in the car from years ago so it may be from there originally?

Cheers

David

tambox · Post by **tambox** » Mon Sep 02, 2013 11:21 am

Out of interest, next time it blows black smoke on start up, turn it off and have a look at the float level, could be a needle seat problem.

David D · Post by **David D** » Mon Sep 02, 2013 2:13 pm

Will do. That would explain the intermittent nature of the problem - sometimes the needle might sit 'right' and other times maybe not

Thanks

David D · Post by **David D** » Wed Sep 04, 2013 8:03 am

Had trouble again yesterday and checked the float level after it stalled - couldn't see the level so must have been either above or below the sight glass. However there was fuel leaking out the carby so I'm thinking it was totally flooded. Once I got it started bowl level settled spot on.
Does look like the needle could be sticking. Gonna have a look today....

David D

steptoe · Post by **steptoe** » Wed Sep 04, 2013 8:15 am

interesting.... next step might be to try a line clamp on fuel to carby hose overnight to see if float level remains correct

tambox · Post by **tambox** » Wed Sep 04, 2013 12:34 pm

There should be some sort of clip (super fine wire, like hair thickness almost) on the seat body, where the needle slides in and out.
If that is missing or bent, it can allow the needle to slide too far out as the float drops, due to fuel evaporation. As soon as you turn the pump on, the inrush of fuel can cause the needle to "stick" in the seat. After a bit of rough running engine vibration, it will free up.
There are several differnt types of clips, some stop the float dropping to far, has the same effect on the needle.
Easy not to see this clip in the kit as it is tiny.

David D · Post by **David D** » Wed Sep 04, 2013 1:33 pm

I took the carb off and all linkages appear to be moving OK. Didn't find any loose screws. Bowl vent valve works. Couldn't see why the needle was sticking but I did the following:

I re-checked the float level and needle clearance. I must have unfortunately binned the original needle and seat after a couple of weeks of good running so I didn't have that to compare. However, I did have the donor carb from 555Ron (thanks again - it just keeps on giving!). I noticed the needle was the same size but way lighter that my current one and it had a more effective looking wire clip on it. My theory is that, if it's lighter, it will float into the seat easier. Does that make sense?
Anyway, I put it back together and it started fine (once the bowl had refilled with fuel) - no flooding or anything and float level returned to normal.
As this is an intermittent problem it'll be hard to know if it's fixed but, rest assured, I'll keep you posted...

Thanks for the help so far.

David D

Silverbullet · Post by **Silverbullet** » Wed Sep 04, 2013 5:53 pm

Heh that little wire clip has caused me trouble in the past; when I rebuilt the carbie I'm running now I put the wrong clip back on the needle/seat. The clip would hold the needle up too much so under heavier conditions/up hill the engine would starve as the fuel ran out.

David D · Post by **David D** » Thu Sep 05, 2013 12:34 pm

After it started OK yesterday I thought I'd leave it overnight to see what happens. There is good news and bad news:

Good news is it started fine.

Bad news is it's running like crap. Stalls pulling away unless I give it loads of revs. When idling, if I gently press the accelerator, it dies. Idle is a bit erratic and feels like it's gonna cut out. Generally feels a bit flat. What the hell have I done?
Just took the top off the carby to check everything and looks alright.
Is it possible I might need to use the same seat to 'match' the needle I used? Float level looks fine.
Could I have caused an air leak somewhere?

Sooo frustrating (and my wife is losing patience too!).

Any ideas?

David D · Post by **David D** » Thu Sep 05, 2013 2:47 pm

Couldn't help myself so I took the top off the carby again and put the seat in to match the needle I'm using - no difference.
There's a massive flat spot on take off and it needs a decent amount of revs to avoid stalling when pulling away.
I revved it a bit in the garage and it struggled a bit at high revs and left a nice black sooty mark on the garage floor.
Float level still looks OK.

I've got no idea what I've done. I'm over it for today and back at work tomorrow so hope it commutes alright.
I'm also moving interstate soon and, in light of the past few weeks performance, a decision was made not to drive the Brumby so it's getting transported down. I would have liked to get it running good before then but that's not looking likely now.

David

David D · Post by **David D** » Wed Sep 11, 2013 8:55 am

Just an update on this for anyone who's interested:

The flat spot on take off mysteriously disappeared overnight and has not returned. I was still having trouble starting the car but at least it wasn't flooding. Turns out I had just put the choke out of adjustment on re-assembly so it wasn't closing fully

.
Anyhow, since I re-adjusted the choke it has started first time every time and no flooding or over-fuelling.
Only thing is now, I could swear it feels down on power since before the rebuild - especially if I try to accelerate hard - but I might just be being paranoid after all the messing about.
I'll keep an eye on it and see how it goes and how the fuel consumption is.

Thanks for all the advice

David D

David D · Post by **David D** » Sat Oct 26, 2013 8:46 am

Guys

Sorry to drag up this old thread but I thought I'd keep all the info in one place.

Anyway, since I last posted, the Brumby has been rstarting and idling great but it goes flat under hard acceleration. It seems ok if I gradually increase speed but if I try to put my foot down quickly it feels a bit... flat.
I thought it might be something to do with the secondary throat but I tried revving the engine and looking down the carb and the butterfly opened.
The timing is on 6 deg (I tried 8 but no difference) but I noticed that it was the same whether or not the vac line was plugged. However, the timing did seem to advance more when revved with the vac line connected so it seems to be working?
I just checked the plunger yesterday and that looked good (just incase I damaged it refitting).
Float level still looks ok through the glass.
Could it be a vacuum leak somewhere or would that cause poor running all the time? Generally it runs fine under 'normal' conditions - just doesn't respond to hard accelerating very well.
Could it be not getting enough fuel somehow?
I don't have a lot of spare time to investigate at the moment as I'm moving interstate the end of November but if anyone has any ideas I'd be grateful.

I'm starting to think of solutions beginning with 'W'.

Cheers

David

RSR 555 · Post by **RSR 555** » Sat Oct 26, 2013 9:08 am

I had similar issues with my EA81 carby in my Brumby, seemed to lack power compared to others that I'd driven and all things seemed to work fine?? Had me worried as I'd only just rekitted the carby but it turned out to be a crappy little black canister thing on the side of the air filter. I have no idea what this thing does and sorry didn't take any pics but try any remove it and try it.

David D · Post by **David D** » Wed Oct 30, 2013 6:28 am

Thanks for the reply but I can't see any canister attached to the air filter - maybe only applies to certain year models.

Cheers

David

RSR 555 · Post by **RSR 555** » Wed Oct 30, 2013 10:41 am

Possibly so. Have you got anyone nearby that tunes carbies? They should be able to check it on their analyser machine.

David D · Post by **David D** » Fri Nov 08, 2013 10:15 am

I was talking to a guy at work and he thinks the power valve could be the issue. Does anyone know how I can test this? I understand you can suck air through the relevant hole in the top plate to check the power valve plunger? But how do I check the power valve itself? I'm not 100% sure how it works.

Thanks

David

RSR 555 · Post by **RSR 555** » Fri Nov 08, 2013 10:54 am

These carbies don't have a power valve like the old holley carbs but they do have an accelerator pump that squirts extra fuel down the throat when you press on the accelerator pedal. To check this is working, just remove the top of the air cleaner and with a torch, shine down the carby and then press the accelerator pedal (or pull on the accel cable but be sure to make sure it doesn't get caught up). Make sure the engine isn't running when you do this and you should see fuel squirt out a small pipe inside the throat. If you don't then your carby is in need of a rebuild.

David D · Post by **David D** » Fri Nov 08, 2013 2:44 pm

Yeah the pump seems to be working fine, I already rebuilt the carb so there's a new plunger and a new ball in the pump. It does feel like an accelerator pump issue - almost like it's not getting enough fuel on acceleration - but I just can't find a fault there.
Isn't that thing in the bottom of the bowl the power valve? I broke mine during dismantling (see previous pic) but was kindly donated another carb to get a replacement from.

David

RSR 555 · Post by **RSR 555** » Fri Nov 08, 2013 4:29 pm

It does look like you have a power valve/jet inside your bowl area... sorry

There doesn't seem to be one in the rebuild kit, so I guess they just need cleaning out.

If I ever see my old Brumby again, I'll take some pics of the piece that the carby tuers replaced on mine, as I had almost the same symptoms as you. Try blocking off some of the hoses and see if it helps.