Over the last week, I've done a head gasket change, new thermostat and a carb rebuild on my 1989 1.7. Today, me and my partner finally put everything back together, and took the car for a run. All seemed ok to start with, and then idling issues and misfires started, so bad that my car died!

We are hoping that this could be down to an issue we encountered during the carb rebuild. I bought a spare carb to be machined and rebuilt, so that I could swap it with the one currently on the car relatively quick and easy. However, I knew nothing about the fact that there are "new" style and "old" style Solex z10 28 34's, and I'd ended up with one of each. Near the end of the rebuild, we encountered this problem and made a decision to use the machined "new" (I believe) base with my "old" top (the bottom part that was on my car was visibly warped!). All seemed to fit ok, apart from one little drilled hole with a filter in, which we couldn't work out what it was for, we ended up filing the filter so it sat flat and left it in.

My carb is now just dumping neat fuel into the chamber and idle is very erratic! Can anyone let me know if this is being caused by the mystery filter, or just the fact that we tried to make a Frankencarb? Could we have missed anything else during the rebuild?

My engine also seems to be running hotter than normal (can anyone tell me what normal should be?!)

Any help on this would be very much appreciated, as I'm left very disheartened and without my daily!

Carbs are the devils work, they shouldn't work as it is. Fk with them and you will lose your soul.

Anyway consider it a learning experience, check everything, get it sorted and feel smug... eventually.

Only the devils gatekeeper with the magic amulet has the power to take apart such things and live.

Running hot? the temp gauge tells you precisiely what is normal, but if you have a hot exhaust manifold, like red hot (and no turbo) you may have the cam timing slightly wrong. But could also be the excess fuel burning in the exhaust, have you checked for flames?

Yeah, you're right

As for the hot engine, I'm hoping it's because of the high idle/amount of fuel. It used to sit happily around the halfway point on the dial, and now it creeps up towards hot and struggles to cool back down.

Fit a weber and claw back your sanity

Do not fit a Weber (well, if you are meaning the Weber replacement they made for the Solex, it's worse by an epic margin. DCOE might be acceptable as long as you only ever use full throttle.)

The major thing I'd worry about in that post is you say it's dumping neat fuel into the chamber. Which chamber? Fuel coming from the fuel pump *should* be being stopped by the float chamber needle valve, which is activated by the float. If the float isn't set to the correct height, or not working, or the valve not sealing due to crap on the seat then fuel will continually enter the fuel bowl and overspill down the venturi.

Did you read Mac's guide on how to overhaul the Solex?

Fuel is coming out through the venturi. Will take it apart again tonight and check the float height again. I will find that guide too! That'd be a great help! Cheers for advice.

Is the float new? They're fairly well known for becoming porous and absorbing fuel. A porous float would affect the level of fuel allowed to enter the float chamber via the needle valve.

Yep, new float.

Has anyone got a copy of the rebuild guide by Mac? I just clicked the link in the resources forum and it's no longer available.

I think CBA found that fuel leaking straight into the inlet manifold of my 1.4 was due to a dodgy carb gasket.

Evening all,

Will try to get my article re-hosted!

I don't feel the hybrid mating of a Z10 REN857 and a REN894 is causing your problems - there are very little differences (your filter being one of them).
If as you seem you are suffering gross over fueling (from the venturi) the most likely cause is incorrect float height (given that you have fitted a new float) or loose or missing main jets (located below the emulsion tubes).

You seem to have addressed common issues such as the base warpage and there actually isn't much you can get wrong when rebuilding a Z10. Which rebuild kit did you use - Webcon's?

Might be worth checking for correct routing of tank return (either from pump or from vapour separator dependant on the system you have) to make sure pump over pressure is not overpowering the float needle valve.

Has the trouble appeared after "only" a carb rebuild or has other work been carried out at the same time - what problems were you having to "need" the work.?

Good luck - Mac.

Really appreciate the reply! The head gasket and thermostat was done at the same time. I believe I had the air leak problem with my previous carb set up, and this over fuelling problem has only occurred since the rebuild. Rebuild kit was from Classic.

We are, right this moment, refitting the carb to the car to try it after some float adjustments (namely changing the gasket for another variant and replacing old floats which seem to sit a lot better). Fingers crossed!

Done that and still doing it Checking and changing a jet now, as it seems very wet.

... Still doing it!

Ahh, I didn't realise Jani's link had failed

Try here:
http://chriscardwell.co.uk/volvo/b172kcarb.pdf

Still not sure about this hot engine business, You need a wot to get a large amount of air in, and air is needed to burn the fuel even in the exhaust, otherwise excess fuel acts as a coolant. Have you got a good water pump? maybe try the old thermostat, and double check the cam timing.

also cylinderhead bolts, oiled, used good torque wrench..no slipping/damaged bolts?