Think i found a very serious carb issue

[Pappa]

If i spray start gas near the three hoses on top of the water pump here the engine revs up.. what are these for?


Is this the restrictor thing?


Here's the gardena thingie..

I think it has something to do with the brake vacuum?

[morgan105]

The 3 hoses are just coolant hoses and go to the manifold and heater, you should'nt get an increase in revs by spraying on to these. The only reason for an increase in revs is that the spray must be getting in to the carb (may just be getting pulled in through the filter as the end of it sits around that area or carb may still have a leak in it at a gasket somewhere, looks awful wet).

The plastic piece in the tube is the restrictor for vacuum so you do have that.

The hose piece is ok to use for the connection but what I would suggest is to replace the piece of wire with a jubilee clip like is on the other end as if it's not producing a good tight seal then you will get a leak from that point.

With the carb being so wet looking it may still be leaking or it may need a bit of adjustment. Also check your breather hoses to make sure they're not blocked especially the one from the rocker cover back to the t-piece connector (also check that) that takes the pipe to the bottom of the carb.

morgan105

[foggyjames]

That is the filter or one-way valve for the brake servo vacuum hose...I presumed we're talking about the restrictor in the vacuum line which forms part of the breather system.

That one is usually very well hidden in the hose which runs from the outside edge of the base of the carb around to the port in the rocker cover. You'd barely know it was there if you weren't looking for it...the hose is in two halves, which are pushed onto the restrictor, covering it completely.

cheers

James

[Pappa]

That is the filter or one-way valve for the brake servo vacuum hose...I presumed we're talking about the restrictor in the vacuum line which forms part of the breather system.

That one is usually very well hidden in the hose which runs from the outside edge of the base of the carb around to the port in the rocker cover. You'd barely know it was there if you weren't looking for it...the hose is in two halves, which are pushed onto the restrictor, covering it completely.

cheers

James

Hm. The gardena hose is the brake servo vaccum hose, which attaches to the one-way valve. The brake servo is working, but i assume that hose isn't 100% airtight, so it should be removed & replaced.

Now the other hose you're talking about, does it run from the base of the carb, into a T-joint, and then into two other places (i assume the rocker cover is one of them)? The restrictor is somewhere in that?

[foggyjames]

There is supposed to be a short piece of rubber hose linking the plastic servo pipe to the inlet manifold. It looks like someone was a bit creative with the replacement when the original split It looks like you could improve on their work, yes...

That's correct. The hose runs from the base of the carb to the T-piece, and the two ends go to the rocker cover and the airpan. The restrictor should be in the second between the carb base and the T-piece. You can tell if it's there because the pipe is a bit hard & straight there...but its pretty well hidden! For this reason, they often get replaced with a straight piece of pipe, which effectively introduces a huge vacuum leak.

cheers

James

[Pappa]

Doesn't the carb look very wet in those photos? Something's not right.

Do you guys think it would be a good idea to give the carb a refurbishing and go over all the vacuum hoses and replace pretty much every vaccum hose i can find? I guess 21 years is too much for a rubber hose

I bought this kit a while ago: http://cgi.ebay.com/ebaymotors/ws/eBayI ... Y.m238.lVI

Still waiting for it to arrive though, but is there anything else i might need? Oh, and I'm having trouble locating carb cleaner, is there anything else i can use? Like electronics cleaner or start gas?

Is it really hard to refurbish a carb?

Is there an easy way to diagnose a faulty fuel pump or ignition? I've been having trouble with the engine "spluttering" every now and then when I'm driving, especially when driving slow in a long queue or similar, and I'm wondering if it's the fuel pump, ignition, carb or something else..



EDIT: Here's a video of the idling when the engine's warmed up: http://www.youtube.com/watch?v=ebPJskgIzHs
Just adjusted the carb to 2.0%CO and set idle to around 900RPM. Notice the shaking and the RPM meter going up and down.

It's much worse when it's cold, the idle drops to around 500RPM!
According to Haynes the idle RPM when cold and the engine choked the RPM should be around 1800-2000, mine's around 1000. I also gotta give it gas real slow or it'll die off, i can't give it full throttle.

[foggyjames]

It is pretty well caked in grease there. A rebuild certainly can't hurt, and isn't difficult to achieve.

As for your other symptoms...I think all the answers you need are in the stickied thread. Essentially, (assuming the carb itself is ok), you're probably looking at a vacuum leak, or a dodgy idle solenoid.

The carb is the first port of call...it could be the fuel pump or ignition, but carb (and intake) problems are so common on these engines that it's worth tackling those areas first.

cheers

James

[Pappa]

It is pretty well caked in grease there. A rebuild certainly can't hurt, and isn't difficult to achieve.

As for your other symptoms...I think all the answers you need are in the stickied thread. Essentially, (assuming the carb itself is ok), you're probably looking at a vacuum leak, or a dodgy idle solenoid.

The carb is the first port of call...it could be the fuel pump or ignition, but carb (and intake) problems are so common on these engines that it's worth tackling those areas first.

cheers

James

Thanks for putting up with me, I'm gonna try everything I've heard so far now.. so no more questions for a while i hope

Thanks for the help guys, much appreciated

Regards,
Jo


Edit: Hey, I've replaced the breather hoses. The one in the carb base was cracked up badly! And it did not have a restrictor I found a solution though, i had a small banana plug that just fit inside the hose! Perfect restrictor thingie i think, hope i didn't restrict the airflow too much though.

It looks pretty good with blue vaccum hoses, I'll snap a pic later..

[Pappa]

I think i found out why the carb looks so wet, it seems the petrol hose feeding the carb is leaking in the area where it meets the carb.

Also check out the last post in my project thread
http://www.volvo300mania.com/forum-uk/v ... php?t=5751

[morgan105]

If the fuel hose is leaking it could cause air to get in and not enough fuel and you can then get all sorts of running problems.

morgan105

[Pappa]

Quick question, I have a Weber 32 DIR, i understand this is a replacement unit, and doesn't work as well in cold climates? That might explain the engine not speeding up at full throttle when the engine is cold?

It's about 14 degrees F outside when i start it in the morning.

Oh and it's hard to start the engine when it's warm.. easy to start when cold, just give full choke and pump twice on the gas and it starts right away..

[foggyjames]

A Weber DIR 32 is the correct carb, unless you have a B14.3E (or something like that) in which case it should be a Solex. Almost all 340s were DIR32 equipped, though. I suspect some sort of carb / vacuum problem is causing your troubles.

cheers

James

[Pappa]

Okay! I kinda crapped the car up on the winter but now when the snow is thawed up i charged the battery and the engine fired on first try and ran smoother than pretty much any other engine I've ever heard. Power delivery is pretty much instant, so i assume the carb was icing when i was having problems with it in the winter. Anyway i assume the carb is working pretty good then, apart from the leaky petrol hose there's no issues i guess.


And later the same day the exhaust broke off at the downpipe junction and the throttle wire snapped. Crap. The thing sounds like a performance monster though, but the neighbors don't seem to like it as much as i do.

[foggyjames]

Hehe Sounds like you've been having fun.

Carb icing....yeah, that would do it. Do you have the 'hot air' hose installed between the air inlet and manifold shroud? My 1.4 never did that, even in very cold weather....although I imagine your climate is a bit colder

cheers

James