Thread: I has me beat .....any suggestions

Hi I had a similar problem with my cd175 equipped v8. Turned out to be a bit of silicone goop in the fuel line attached to a thread that was blocking the needle valves moving back and forth depending on fuel flow.
Removed the needle valves cleaned em out and lived happily ever after.
The problem was I checked them but didn't remove them initially they flowed fine until fuel flow was high and the glob of silicone blocked one Carby and forced the engine to run lean.
Maybe put in a temp fuel pressure gauge.
Fwiw I spliced in my little outboard fuel tank into the fuel system to isolate the fuel tank pump side of things.
Clive

I didn't see new spark plug leads, rotor button or distributor cap in the list.

With 98 octane you can run up to 10 degrees BTDC advance no worries. As for your problem, it sounds a bit like its running on one carby only?

Check that timing again. Should be BTDC not ATDC.

Thanks everyone for your input,

Graeme - yes you are right havent changes leads, distributor cap or rotor as I did'nt believe (more hoping) that they could'nt fail all round the same time as my electric fuel pump and carbie issue but are on the list to replace.

Bearman / bee utey - rechecked timing was on 6 deg ATDC, reset it first to TDC and it had no power - nothing reset it to 6 -10 degrees BTDC accellerates better and while she still has a misfire she certainly does run better......thanks gentleman.

Clive 22 - I'm leaving your suggestion to last as it means pulling off the carbies again (bugger) although I did replace both needle valves with new ones. But I'm willing to strip them and check needle valves as suggested.

I'm also thinking as she has been sitting for a good 5 months, with the choke being on (now fixed) and it running very sooty could that be an issue.
Tonight afer resetting the timing it was the first time I actully felt comfortable doing a number of laps around my street and progressively going further out without the fear of breaking down.
Thinking could be about time I take her for a longer run to blow out some of those cobwebs ......

Its just nice to be in her and at least driving a short distance

Cheers

Baggy

Hi Everyone,

Since my last post I have been driving the Rangy around my back streets with the engine misfiring.

I thought (as per my last post) that as she has not being driven much since Sept last year .... sitting around .....problems with auto choke stuck on (black soot from exhaust) that she may
need to be driven around to blow out the cob webs.

The carbies seem to be working, when cold, pull out the auto choke (turned manual) she starts.
She idles around 1100 rev's (it's a 3 speed auto) but when put into reverse or drive will drop to 850 rpms.....however there still is a rich fuel smell.
You can turn her off when she warm and she will restart with just a turn of the key ....something she wouldn't do before.

What's annoying is at times, not always it won't kick down or accelerate......you take off there's nothing.....it slowly starts to rev and eventually it will build up speed and ......away she goes.
I'm embarrassed as you hear this excellent burble from a V8 and the other night I was tailgated by a scooter till she eventually acellerated enough to pull away.

So last weekend I decided to step back and relook at the problem again.....

I pulled out the plug leads while engine was running and found spark plug No2, 3, 5, 8 would not make the engine run any differently. Pull out 1,4,6,7 leads and engine would noticeably shudder.

I then individually pulled out offending spark plugs (they were sooty) cleaned them, earthed and checked spark with engine running ... 2,3,5 had a yellow spark and number 8 was shorting off the side of the plug. ( these were new plugs)
Replaced number 8 with old plug and it now had a blue spark when earthed with engine running.

As per Graeme's suggestions I had the necessary $$$ to:

1) Replace Distributor cap with new Bosh replacement.
2) Replace Distributor rotor with new Bosh replacement.
3) Replaced spark plug leads.
4) Rechecked timing and set it to 10 degrees BTDC

I put a new coil in last year, swapped it over with the old coil and the result was still the same?.misfire.

Refitted the new coil back.

You can feel the vibration through the steering wheel.... it pulls away and when you get to into top gear it actually drives quite nicely.

The engine at idle sits and runs beautifully with no tell tale increase or lowering of rev's .....accellerate from under the bonnet it seems like a slight misfire when rev'ed up.

Where should I go from here ?...


Appreciate all suggestions


Cheers


Baggy

One carby running rich causing half of the plugs to fuel foul.
The motor will not idle and will clear its self at high load and rpm.
Check needle and seat/float level.
Also check for PVC valve and brake booster taking too much vacuum.
Block off the PVC and booster pickups on the manifold and see if it improves.
What does the jet adjustment tool look like that works though the dash pot and where do you get one from.
It is very unlikely to be a spark problem as it is running OK at high rpm which is when the spark would most likely fail if at fault.
Ron

Purchased the special tool for adjusting main needles (through dashpots) and believe that I have them unscrewed (anti clockwise) as far aspossible without them disengaging from the adjusting screw itself.

That is not how you set the needles!
You may have one carby full rich is you have screwed out the needles. the carbys work by the mixture being set by the gap between the main jet and the needle. The needle is tapered so that the mixture at idle is maintained through the demand/throttle range.
On those emission carbs, I would first set the needles about half way through their range. Then slightly lift each needle/piston with a small screwdriver with the engine idling . The engine revs should rise momentarily then stumble. If the engine revs rise and stay risen it is too rich, if they fall immediately without rising it is too lean. To adjust if rich, screw the adjuster clockwise or in to lean and vice versa.

This should be done after you have set the synchronization with a Unisyn or just a bit of tube in the carb throat just next to the piston. When the suction noise is the same the carbys are synchronized.

The best way to set the mixtures is with a colortune, which replaces one plug with a clear plastic spark plug and you adjust the opposite carb mixture until the combustion colour is blue with yellow flecks , just like a gas stove burner.
Regards Philip A

BTW, 727 auto 3.5s don't really accelerate, they just gain speed gradually! LOL . It is probably normal to be out accelerated by a scooter.