Air leak?

[Elstro1988]

Help!

Just managed to get another year's MOT out of JB (eventually) but it's really poorly..again.

Basically the engine (1.0 OHV) is running very badly. It idles roughly and stalls a lot. It's also very difficult to start, and when starting from cold, the engine has to be really revved to get it going and needs quite a lot of choke even though the weather's not been that cold. There's a hissing noise coming from it as well. It's driveable...just.

The mechanic who did the MOT and the repairs, reckons it's an air leak in either the carb or inlet manifold.

I've been consulting my Haynes manual and several possibilites (dirty carb, ignition timing off, fuel starvation etc).

Last year I had new plugs, leads, points, dizzy cap, and coil, plus oil filter as it was suffering similar problems around this time last year. I only want to see what others reckon before I even attempt to fiddle about under the bonnet as I can't afford to be ripped off by a garage!

Earlier this year I did put a more efficient filter element in it (a K&N one) and I recently put the older one from the last service in to see if it makes a difference.

Help!

[Nobby]

Sounds like you have answered your own question mate id check all the basics 1st

[marc69]

Carb or inlet, I once had exactly the same problem with my 1.0 ohv. It was because one of the bolts that secure the carb had snapped.

[Trivs_Tom]

got a similar problem with the 1.0, sent it off to a garage to sort it out and MOT it at the same time. i'll let you know when i do mate

[dougie_boi]

small pipes from air filter housing that go to the back of the carb havent came off?

[Elstro1988]

Thanks for the suggestions, I will take a look at the air filter housing. So this seems to be a common problem with the OHV engine?

I probably did ramble in the OP. Basically, it cruises and accelerates fine, but when decelerating whilst approaching traffic lights, junctions etc, the idle is horrendous and will sometimes stall completely - I can only prevent this by either constantly covering/blipping the throttle or pulling the choke back out when stationary just to keep the idle speed up.

Unlike many PNGers JB is my daily driver so this is stressing me out loads, especially after I just spent ridiculous amounts of money getting it through another year's MOT!

Please keep your answers coming, the more help I get the better!

Update: Today (9 Nov) I took a look at the carb and noticed that the sealing ring between it and the filter housing has snapped. I've hastily taped it up and put it back in place but it still idles roughly...so I don't know if that has caused the leak....hoses seem OK but I'm not sure.

[dougie_boi]

gasket under the carb?

[Trivs_Tom]

mine turned out to be the ignition coil mate, sounds like a very similar problem so get that checked out?

[brainsnova]

Time for an xe

[Elstro1988]

If I could afford an XE and associated running costs, perhaps. Until then the 1.0 is suited to my budget. I have to wait until payday before I can get it checked out, been a tricky month money wise.

Video of the idle:


http://www.flickr.com/photos/elstro1988/6350224502/

This is the broken sealing ring - it fits in that ring around the top of the carb and seals the space between the air filter housing...people don't seem to know what it is. The carb and inlet don't appear to be cracked but the carb is filthy and another possiblity is a blocked idle jet.

http://a7.sphotos.ak.fbcdn.net/hphotos-ak-snc7/s720x720/390923_10150923802060162_601420161_21759965_131062 1147_n.jpg

I had the coil replaced last year because of similar problems....mind you it's been more difficult to start of late so possibly. Won't rule it out.

[marc69]

i had coil issues before too, the supplier gave me a lucas one, it was rubbish, ended up going for a 2nd hand original. I am sure it's an air leak gap between the carb and inlet.