cluey on carbies?

[kurbn]

I'm pretty green when it comes to carbies and hoping someone here might have more of a clue.

G13a Suzuki motor with the aisan 2 barrel carb. When I go off road I have been experiencing running issues and fouling plugs up. I don't give it a hard time and majority of the time its putting around. It started doing this out of the blue, idling low and overfueling it to the point the plugs foul up and the idle is fluffy. It will accelerate fine once you open it right up.

I decided to run a carb service kit through it, found the needle/seat is sound and operates as it should, float level was to spec. What I did find is the accelerator pump was leaking fuel externally of the carb past the rubber plunger boot. Also the leather cup on the shaft was pretty stiff and looked pretty cactus.

does that sound like what could of been the issue? not really sure what the leather cup is designed to do.

pic of plunger -
http://img.auctiva.com/imgdata/1/4/6/3/5/8/4/webimg/508864276_o.jpg

[S85FI]

The leather cup seals when fuel is there. It forms a plunger and squirts fuel threw a small spigot just on the inside of the venturi tubes.
The rubber grommet is a dust seal.

If itleaks it wont squirt fuel and it will bypass the bore.

If it doesn't work,

Car hard to start and no fuel is squirted into venturi and no fuel in manifold.
Car will also have a flat spot each time you accelerate.

The kit you have there isn't a full kit. Seams a bit light on ( haven't worked on carbies in 15 years but did my time on them in a carbie shop)

The carbie will have idle solenoids that need power for low rpm. Also secondary air jets for anything above ~800rpm.
If it is the carbie you will need to over haul the whole thing. Test all powered circuits. Blow all holes and vacumme pump all vacume lines for blockages.

It's a pain if it is the carbie. .... get a book and follow the pictures.

[-Luke-]

Tell me more about the leather cup seal :p

[kurbn]

cheers for that very helpful.

I have the genuine suzuki manual on doing a full recon. They point out all the ports that need carb clean sprayed into and blown out with air and what steps to take, not a bad book.
I took all the jets out and it blew a bit of brown crap out of the ports. There wont be anything lodged in there now if there was anything. I would of thought it would be running lean tho if something was blocked.

I will check all the vac lines when I get home tonight and fire it up. Thanks for your help :)

If its still shot ill prob hand it over to Jim at perth carby specialists, I know when he rebuilds these sierra carbies he acid baths them and are pretty hit and miss on the diaphragms on them.

There is also a air mixture screw (non tamper) type on the base, this tells me not to fuck with it. Is this something that should be well left alone? Ive heard of people cutting a slot into it
so its adjustable.

[S85FI]

cheers for that very helpful.

I have the genuine suzuki manual on doing a full recon. They point out all the ports that need carb clean sprayed into and blown out with air and what steps to take, not a bad book.
I took all the jets out and it blew a bit of brown crap out of the ports. There wont be anything lodged in there now if there was anything. I would of thought it would be running lean tho if something was blocked.

I will check all the vac lines when I get home tonight and fire it up. Thanks for your help :)

If its still shot ill prob hand it over to Jim at perth carby specialists, I know when he rebuilds these sierra carbies he acid baths them and are pretty hit and miss on the diaphragms on them.

There is also a air mixture screw (non tamper) type on the base, this tells me not to fuck with it. Is this something that should be well left alone? Ive heard of people cutting a slot into it
so its adjustable.
Mixtures arw set up for a motor with good compression etc. Screw is generally slotted for worn engines.
Blowing must be down both ways. Often it makes problem worse. The dirt is ever so small to blkck a jet or air passage.
A good vacume test to see if the carbie is leaking internally is to cup your hand over the top of the carbie so you are sealing the air going into the carbie. Do it slowly. If done quickly the car will stall. If done slowly and there is an internal vacume leak the rpm will risefrom 100 -1000 rpm pending how big the leak is.

Seak the shop you're talking about. its just too hard if you not sure how they work.

Another thing is when car is at idle spry carbie clean around the base and manifokd. If rpm goes up your leak is external.

Just take it to someone that plays with carbies.

Once you oull it apart you will have 50 parts laying around. .... and ball bearing and sleaves will fall out from inside passages. ... which must go back in the right tubes or it wont run right.

Good luck :)

[S85FI]

Tell me more about the leather cup seal :p
This link should help with your leather cup problem ;)

http://tickets.myguestlist.com.au/53d64ee21e8ce/club-freak-caged-29th-august-2014/

[d1mitch]

get rid of that aisin crap. its a heap of shit carb.

i put a weber 32/36 on my G13a and the difference in power is night and day, and the simplicity of the weber without all the polution control and eacess crap on there compared to the aisin make everything much easier to work on.
webers are knownt though to have some issues with steep angles so i mounted my carb backwards (float bowl to the firewall) as this is a bandaid fix for the problem, so the engine will only overfuel on steep down hills (much better than stalling up a slope).

when i eventually build a new engine for the sierra i will put a 38/38 on it for maximum power!!!

[kurbn]

thanks S85FI's, great help mate. Carbie guys are a dying breed.

Mitch, I like what you're saying. Years ago when I worked at suzistore all I was ever told that was webbers were rubbish on these things and a pingpingpingping to tune. Perhaps so if they are worn out carbs. I have heard of the float closing off before, but I have had a few instances with the aisin going up verticals of the same thing. How did you find it if you are driving into a steep trench and being careful. Is it more long down hills or at any point you are at a 45 degree angle it cuts it out instantly.

I started it last night and the idles much better, revs up smooth but wont really know the result until I take it out bush. I know getting a proffessional job done on it will be in the relms of $350.

but for a bit more could have a webber conversion
http://www.ebay.com.au/itm/Suzuki-Sierra-WEBER-carb-conversion-kit-suit-SNORKLE-/331245787743?pt=AU_Car_Parts_Accessories&hash=item4d1fc99a5f&_uhb=1

[r31]

Figure this is a good thread to hijack, are there any legal issues with changing to non standard carbs?

[S85FI]

Figure this is a good thread to hijack, are there any legal issues with changing to non standard carbs?

Most Holley, Webber type carbies won't comply with emissions. Also most aftermarket have mechanical secondaries and not vacuum. No idle solenoids etc....

If pre emission days... bang on what ever ya want ;o)

If you got a Rochester (Holden/Chev) or a Thermoquad/Carter (Ford with Bakelite / plastic body ) you can get them to flow out just much as a 750 double pumper mechanical secondary Holley's etc.

The Rochester we could flow out to 780 cfm. Never modded the Ford version but have seen good results.

[Passage GT]

The Roch is a great carby if you can find somebody that knows how to properly modify and tune them.
Can get rebuilt ones cheap too these days.

[S85FI]

The Roch is a great carby if you can find somebody that knows how to properly modify and tune them.
Can get rebuilt ones cheap too these days.

Best thing about the Rochester is two small primaries and two big fuck off secondaries. The fuel jets aren't fixed hole size. Has a tapered needle that lifts with engine load giving the main fuel jet a hole around 3.5-4mm x 2 at wot. Massive fuel and air flow whilist economically viable when not under laod.

An awesome carbie.

[upgarage]

You probably dont want to hear this but i just sold 2x webber 32/36 carbies with g13 manifold
1 went east and the other sold locally (yesterday)

The guy who bought it was a bit hesistant so you may see if pop up for sale
Had adj fuel pressure reg and elec choke

extracting power from the G13 is false economy IMO
I've gone the coilpack baleno G16b route in both my sierras

[r31]

Most Holley, Webber type carbies won't comply with emissions. Also most aftermarket have mechanical secondaries and not vacuum. No idle solenoids etc....

If pre emission days... bang on what ever ya want ;o)

If you got a Rochester (Holden/Chev) or a Thermoquad/Carter (Ford with Bakelite / plastic body ) you can get them to flow out just much as a 750 double pumper mechanical secondary Holley's etc.

The Rochester we could flow out to 780 cfm. Never modded the Ford version but have seen good results.

Thanks, probably going with bike carbs, it will be a prick to revert to a stock setup if I get stickered though

[kurbn]

You probably dont want to hear this but i just sold 2x webber 32/36 carbies with g13 manifold
1 went east and the other sold locally (yesterday)

The guy who bought it was a bit hesistant so you may see if pop up for sale
Had adj fuel pressure reg and elec choke

extracting power from the G13 is false economy IMO
I've gone the coilpack baleno G16b route in both my sierras

yeh, I used to work at suzistore so seen a few interesting conversions at ditching to fuel injection. G16b with jimny injection and 1600 injectors is the most desirable.
I had a peak at the Swift TBI and the carby looks even more of a headcase to deal with. The problem with G16 blocks is people that sell them are wrecking the car
because something has gone wrong, usually an overheating problem and that normally comes with a cracked block.
Anyone you can trust to sell you a good complete motor will be a couple of grand. Can be a gamble buying a wrecked car if a crack hasn't shown its face yet.
Once its cracked its in the bin. However if its a good motor they're a lot of fun! They go pretty well even in a baleno.

the problem with the 1300 I find is the lack of top end on the highway which really stresses the motor having to drive it at 100ks in 4th gear. And lack of power to climb sandy hills.

[upgarage]

yeh, I used to work at suzistore so seen a few interesting conversions at ditching to fuel injection. G16b with jimny injection and 1600 injectors is the most desirable.
I had a peak at the Swift TBI and the carby looks even more of a headcase to deal with. The problem with G16 blocks is people that sell them are wrecking the car
because something has gone wrong, usually an overheating problem and that normally comes with a cracked block.
Anyone you can trust to sell you a good complete motor will be a couple of grand. Can be a gamble buying a wrecked car if a crack hasn't shown its face yet.
Once its cracked its in the bin. However if its a good motor they're a lot of fun! They go pretty well even in a baleno.

the problem with the 1300 I find is the lack of top end on the highway which really stresses the motor having to drive it at 100ks in 4th gear. And lack of power to climb sandy hills.

both of the baleno's i bought were well under a grand. closer to 500 so they are out there you just have to be quick
both are running complete cars

thought the cracked blocks only applied to the vitara g16b's

1.3 lack the torque to sustain highway driving and for 4x4, especially once you start fitting bigger tyres..etc

[kurbn]

nope, balenos also. Cyl 4 on the inlet side about the height of the welshplugs is the most common spot. Vitaras will do it if its been cooked, jumped or the gearbox to block braces havn't been fitted where the front end is bounced around off road. (chassis flex inwards)

balenos will only do it if they have been cooked.

I had a look on gumtree the other day after your last post, few on there at the time around the 1000 buck mark as you say :)

[kurbn]

So..Driving it around for the past week its been mickey mouse apart from some minor idle adjustments which i've been fine tuning .

also checking the plugs a lot this week, perfect mixture. At this point I figure the clean down has done some good.

HOWEVER. tonight I decided to take it through a track and try it out... lots of woops (up and downs) and some limestone rocks I had to bounce over. Within a few minutes of doing this it starts showing signs of idling rough. Went over a section of bumpy track with rocks ect.. Then its back to idling at 200rpm and running rich.
Coming home now its slowly clearing up. So it has something to do with bouncing. I assume the float has something to do with it. Plugs are now all fouled up again.

I never touched the float level on the carb as I measured it to spec "7mm" off the deck according to suzuki specs..

Fucking odd.

[S85FI]

So..Driving it around for the past week its been mickey mouse apart from some minor idle adjustments which i've been fine tuning .

also checking the plugs a lot this week, perfect mixture. At this point I figure the clean down has done some good.

HOWEVER. tonight I decided to take it through a track and try it out... lots of woops (up and downs) and some limestone rocks I had to bounce over. Within a few minutes of doing this it starts showing signs of idling rough. Went over a section of bumpy track with rocks ect.. Then its back to idling at 200rpm and running rich.
Coming home now its slowly clearing up. So it has something to do with bouncing. I assume the float has something to do with it. Plugs are now all fouled up again.

I never touched the float level on the carb as I measured it to spec "7mm" off the deck according to suzuki specs..

Fucking odd.

Make the float slightly lower so there is less fuel in the bowl?
Check power to any solenoids to the carbie and wiggle them. Could be breaking a electrical cuicut.

Either way... too hard over the web :(

[kurbn]

called Jim @ Perth Carby and he suggested what you said. There's like a hook/tab that stops it dropping down so far and suggested to bring that down. He said If its the bounce that's giving you the grief and it drives fine on the road it will be the float.

[S85FI]

called Jim @ Perth Carby and he suggested what you said. There's like a hook/tab that stops it dropping down so far and suggested to bring that down. He said If its the bounce that's giving you the grief and it drives fine on the road it will be the float.

The other thing you can do is modify the needle and seat.

Buy a needle and seat kit so you have one good one.
Set float low so when bouncing car doesn't over fuel.

Now the trick...

Set the float low enough it works but the car starves of fuel under high rpm load. Say 70% capacity.
With a fine junior hacksaw or nail file, slit the needle and seat on the sealing side. That way when fuel demand is there it will flow the fuel into the bowl via standard holes and the slit. This will compensate for the lack of volume. But will also stop fuel splashing into the venturi.

If you need more fuel do a second slit on the opposing side of the first slit.

Good luck.

Normal hacksaw blade is too thick. Nail or fine points file is just right.

Your fuel pump will deliver the volume. Keep in mine your fuel line is around 6-8mm and your hole in the needle will be some 2-3-mm.

[kurbn]

Sorted son! Took it up an angry limestone hill and its good as gold. I lowered it 3mm and bent the tab slightly that stops the float dropping so far. Acceleration is better too! Had a good bounce about for 3 hours.

Cheers for the help mate :)

[S85FI]

Sorted son! Took it up an angry limestone hill and its good as gold. I lowered it 3mm and bent the tab slightly that stops the float dropping so far. Acceleration is better too! Had a good bounce about for 3 hours.

Cheers for the help mate :)

Glad it worked :)