My First 7

[Andy Bennett]

worth taking plugs out to check spark on all and clean plugs.
Then perhaps blown head gasket?
Guess you don't have compression tester available?
Don't drive further if it is head gasket as might be filling cylinders with water.

Andy B

[WJPez]

worth taking plugs out to check spark on all and clean plugs.
Then perhaps blown head gasket?
Guess you don't have compression tester available?
Don't drive further if it is head gasket as might be filling cylinders with water.

Andy B

I will check the plugs next to see what they look like, they were replaced less than 10 miles ago so should it should be obvious if there isd a problem.

Wayne

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I have removed all the plugs, they were all black and sooty. I have cleaned them all and cleaned the ends of the pug leads where they connect with the spark plug. I managed to get to the end of the yard at work and it stopped running and will not restart.

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I have just removed the carb (Zenith). The bowl is loose (hanging off).

Wayne

[Andy Bennett]

i am guessing it doesn't simply need tightening or the bolt threads have gone so won't tighten?
if threads have gone and problem is lack of petrol and messed up mixture you could strap it back tight (seen it done for testing with cable ties) to see if that solves it, then get thread helicoiled to fix permanently.
Andy

[WJPez]

i am guessing it doesn't simply need tightening or the bolt threads have gone so won't tighten?
if threads have gone and problem is lack of petrol and messed up mixture you could strap it back tight (seen it done for testing with cable ties)  to see if that solves it, then get thread helicoiled to fix permanently.
Andy

I have tightened the bowl, i undid the 2 fixings on the choke and it has all fallen apart in my hand. I am struggling to get it back together. The large spring is causing issues.

Wayne

["Slack Alice" Simon]

It takes a bit of fiddling to get the choke back together.

Keep trying, and eventually you work out how it goes.

There may be a diagram of the carb on one of the club websites.



Just for the help it might be:

When I take a carb bowl off:

I throw the fuel in it on to a flat surface like a paving slab - this tells you if there is water in the system, you can see the bigger blobs of water on the evaporating fuel.

Then I blow through the little nozzle on the outside of the bowl, with my finger over the biggest hole in the top surface (the compensating well).   You should get two jets of fuel to show the main carb jets are not bloocked.

Two simple diagnostic tests if "running rough", and the first thing I do.

Simon

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PS.

When putting the carb - or nearly anything on a Seven - do not overtighten, or you will strip the threads.

If the threads in the bowl have really gone you can bodge a certain amont of grip with a bit of card down the holes, and then, as already said, use cable ties to hold it together.   It will run for ages like that, but not so easy to take the bowl off to do the checks previously suggested.

Simon

[WJPez]

It takes a bit of fiddling to get the choke back together.

Keep trying, and eventually you work out how it goes.

There may be a diagram of the carb on one of the club websites.



Just for the help it might be:

When I take a carb bowl off:

I throw the fuel in it on to a flat surface like a paving slab - this tells you if there is water in the system, you can see the bigger blobs of water on the evaporating fuel.

Then I blow through the little nozzle on the outside of the bowl, with my finger over the biggest hole in the top surface (the compensating well).   You should get two jets of fuel to show the main carb jets are not bloocked.

Two simple diagnostic tests if "running rough", and the first thing I do.

Simon

---

PS.

When putting the carb - or nearly anything on a Seven - do not overtighten, or you will strip the threads.

If the threads in the bowl have really gone you can bodge a certain amont of grip with a bit of card down the holes, and then, as already said, use cable ties to hold it together.   It will run for ages like that, but not so easy to take the bowl off to do the checks previously suggested.

Simon

Thanks, I have managed to get it back together. Just need to test it now.

Wayne

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It runs, going to leave work now and see if i can make it home.

Wayne

[Andy Bennett]

Did you get there?

[WJPez]

Did you get there?

I got home ok. It seemed to be running ok. There was a very slight leak from the carb banjo bolt washers. I am joining my local club on Monday night and they have some spares there, so I hope they have some washers. I will also buy a dizzy cap, rotor arm, points and condenser. I was surprised that the carb bowl was not sealed in place or had a gasket or o ring.

Wayne

["Slack Alice" Simon]

The carb bowl just sits there, usually nothing spills out if the needle valve above the float is in good condition.

Even with new washers the petrol unions often leak.

The temptation is to keep tightening the joints.   Don't over do this.   I always use the lowest grade Loctite as a sealant, it works nearly every time.   "Screw" grade or something like that, not "stud" or "bearing fit" grades.

Simon

[Andy Bennett]

Excellent, good to hear that it is just a carb problem. you at least know what you are dealing with.
My banjo bolt also leaked. The thread into the carb is often worn and has little strength. It can be helicoiled with care as the surround can split.
New fibre washers help as old ones are often hard and don't seal well. They are standard fibre washers, I got my last ones in one of the multipacks you buy in Aldi etc.
I used some gel type loctite threadlocker (as Simon says, not bearing fit as you won't get it apart again without heat), on the thread and then some araldite around the washer and has held well for about 5 years now with no further leaks.

good luck
Andy