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Engine Racing Woes


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I have a 54 TR2 and I’m after some advice as currently my car is hard to start and once started, the engines races, then cuts out after a few seconds.

 

I need to encourage it to start with Easy Start spray into the air filter. It doesn’t want to start without it, although once started, after a few seconds of high revs, the revs will drop and to avoid the engine dying, I have to pull the choke out fully and it races again. Once the choke is pushed back in, after a couple of seconds the revs drop again and the engine stalls, so the choke is pulled out again…. repeat etc as you get the idea! The throttle doesn’t do much.

 

It was running well, however I had a blowing exhaust as one of the studs had sheared that attached the exhaust to the manifold so the carbs were removed followed by the manifold and the stud replaced etc.

 

At the same time, I replaced the fuel tank and ran a new fuel pipe from front to back.

 

I’ve Googled to my hearts content and I’m not getting anywhere, however would have thought that this was a fuel issue as opposed to anything else (as I need Easy Start to start it). However, once the car starts, it will run, although then requires choke, which would usually suggest a mixture issue. If I disconnect the fuel pipe to check the petrol just before the carb, fuel is being pumped through quite happily. It doesn't pop or bang so I'm happy that the manifold is secured correctly.

 

Ideally I don’t want to create additional issues, so … does anyone have a methodical way of troubleshooting this one?

 

Many thanks

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Sounds like it could be an air leak - probably the first place to look is the carbs and inlet manifold which you removed and replaced. If it races without throttle then air must be getting in somewhere. Did you replace the gaskets when the inlet manifold was put back and is it all seated and sealing properly?

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Does the car have original SU H4 type carbs? Have you touched the float chambers?

 

If so are the overflow/spill vent tubes on the tops of the float chambers actually venting to atmosphere?

 

The lower fibre washer that fits between the vent pipe banjo and the float lid is not a snug fit around the tube bolt, it has sort of cut outs in the id

see image.

I once fitted regular fibre washers and the car ran like a "bag of poo" until I went back to the correct items.

 

Peter W

 

 

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Thanks chaps. The carbs are original and I haven't touched anything on the carbs at all or ever topped up the dash pots, so .... will have a look at everything you've suggested this weekend and let you know.

 

Easy Start Iain is a thing of miracles!!

Edited by Devs
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"Easy Start Iain is a thing of miracles!! "

 

Not if it's the stuff that you buy from aftermarket Auto stores it isn't, thats the stuff that because of it's uncontrolled detonation breaks your piston rings and causes you to have to strip the engine and rebuild it.

 

As regards your engine running problems it sounds like a massive air leak on the manifold area, maybe a manifold not seating correctly, I should strip it off and starting from there reassemble carefully making sure all gaskets are good and the manifolds both inlet and exhaust seat correctly on the gaskets and pull down evenly when tightened. Then refit the carburettors and confirm the float levels are set correctly and try again.

 

Mick Richards

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Cheers guys. Will break down and reconstruct at the weekend. Also.... very interesting and educational information on Easy Start. I will use with caution in the future.

 

 

One last question. What grade oil goes into the SU dash pots?

Edited by Devs
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I use 20-50 or a straight oil at 20 grade. Three in one oil is sometimes recommended which is about 17 grade.

 

Mick Richards

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Just a quick update on this one. I whipped the carbns off yesterday evening and discovered a washer between the gasket and the carb body, so absoutely correct, there was a air leak (no idea how that got there). Carbs were replaced and the same symptoms occured after starting which was disappointing.

 

I ran out of time, so have a deeper dive at the weekend!

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very carefully try spraying brake cleaner fluid around manifolds/pipes/any orifice connected with the air intake side of the engine...I must stress be careful especially near the exhaust manifold but if you have an air leak and this stuff gets in your revs will rise even more but it will show results

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Nigel,

A good trick indeed, works really well. Just make sure you buy the right brake cleaner, some of the "modern" stuff is not flammable anymore....and won't do any good.

Yves

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I had poor starting as described and had to use Easystart. Eventually discovered poor compression . Valve seats burned and needing replacing/reseating. ( I also replaced liners, pistons, rings etc etc but I'm fairly sure the real problem was the valves. You will put in new harder valve seats and not need to worry about burning them out in future.)

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  • 3 weeks later...

Hi chaps, just recommencing this thread as I''m still having issues.

The engine fires and runs with Starter Fluid, so I know that everything is working as it should do, however once I stop spraying, the engine dies.

 

My petrol pump works correct and squirts petrol quite happily, however when I then attach the petrol pipe to the carbs, it doesn't continue to pump petrol into them. Its as though the petrol pipe into the carb is blocked. You can't blow in to it either.

 

My vacuum advance pipe is connected and having researched I know this increases the timing as required so should be unrelated to this issue.

 

Before I rip the carbs to pieces, anyone have any ideas?

 

Thanks

 

Steve

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Immediate update. I take the vacuumn advance off and the engines starts and runs like a dream.

 

I'll be playing with it for the rest of the day! Can somebody let me know why this would be. I have very limited knowledge of carb/ignition related issues aside from basic info.

 

Thanks!

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Steve, Where does the vac advance pipe connect to? It should be like this:

http://www.britishcarforum.com/bcf/showthread.php?67403-TR3A-Vacuum-Advance-Hook-Up

Peter

Edited by Peter Cobbold
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Stale petrol

Badly setup carbs

float chamber valve stuck shut

choke not operating

fuel pump not working

blocked fuel filter (if you have one)

leak in manifold

poor compression

 

etc

 

Bob.

Edited by Lebro
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