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Triumph TR6 - Hard Starting

The engine takes a long time to start after the car has sat overnight. It acts like it has run out of gas and is being started with empty float bowls. After that it starts quickly and runs great. The longer it sits the longer it takes to start.

what are the possible causes?

Ken

L Caya

Ken, are you using an electric fuel pump or mechanical?
db
Doug Baker

db
Mechanical. I just replaced the original pump with a MOSS replacement hoping to eliminate this proplem and a fuel smell. The fuel smell is gone, but, I still have the starting issue. Its like the carbs drain over time when the engine is not running.

Ken
L Caya

"Its like the carbs drain over time when the engine is not running. "

Bingo!
With going back and reading your post again. How long since they have been rebuilt?
DON KELLY

Don,
Bingo???

What component of the carbs would cause the draining?
L Caya

Check your plugs
DON KELLY

Plugs are NOT part of the carbs, Why check my plugs??
L Caya

See if the fuel is draining into the manifold and they would be wet and sooty
DON KELLY

Plugs are good
L Caya

OK here is another problem popping up lately. With the new gas the percolation effect is greater.
Basically the fuel is boiling away .
Do you have a stock exhaust?
Many owners are buying heat shields. Specially in your climate
DON KELLY

Stock exhaust and it has been cool weather, upper 60 and low 70.

Is it possible that the fuel is draining back to the pump/tank?
L Caya

Ken

Going back to Don's question about if and when the carbs were rebuilt. Have you?

Are the fuel bowl floats set correctly?
I put in a new fuel pump only to have it fail after a couple of hours of use. Maybe not getting a lot of fuel in the bowl to begin with due to one or the other of these.

If the needle valve in the carbs are not setting in the fuel bowl outlet fully when teh engine is off it will allow gas to evaporate faster.

I doubt the fuel is draining back. There are supposed to be check valves in the fuel pump that prevent back flow and the fuel tank level may be higher than the carbs which would not allow that. As well the inlet to the fuel bowl is above the level of the fuel in the fuel bowl.

What kind of emission control do you have? If there is a vacuum in the carbon canister for some period following turning off the engine it may cause the fuel in the bowl to evaporate off more quickly.

Some ideas I am throwing out there to consider.
Michael Petryschuk

Ken ,have you checked to see if the plugs on the bottom of the float bowls are leaking? After you shut down run your fingers along the bottom of the bowls and see if they are wet with gas. If so, O rings.

Rob
rw loftus

I would think he could smell gas if that was the case.
DON KELLY

Don is right, I have no gas fumes and there is no leak.
I just bought the car last August and don't know if the carbs were rebuilt, I suspect not.
It seems to be internal to the carbs, and it happens quick enough to think it's not evaporation. Noticable within 2 hours of sitting.

Ken
L Caya

Ken, I don't have a clue, other than it's obviously fuel related (or at least seems to be). Maybe get a kit and overhaul one carb and you may discover the culprit when you open it up. I would not open up a carb without a rebuild kit, at least gaskets and O rings. My $.02!!
db
Doug Baker

Thanks Doug

Thats the direction i'm considering.

L Caya

Ken, OTOH, it may be the other carb and not the one you opened or both!! Yeah...2 kits!
db
Doug Baker

Have you checked to be sure that both choke cables are secure and actually operating the choke(s) when the cable is pulled out to start?
Brent B

Oh Brent, that would be to easy
DON KELLY

Yes, both are attached and operating correctly
L Caya

Well, I second the thought that drain-back from the float bowls to the tank is highly unlikely. And I don't think the gas would evaporate away after a couple of hours of Connecticut swelter.

It could be that the needle valves are sticking in the shut position when off. Maybe some marvel mystery oil or something of the sort would loosen them up.

It could be that the general carb mixture setting is too lean. What do the plugs look like?

For starting in general, when cold, pull out the choke and lock, then hit the starter. DO NOT depress the gas pedal. When warm, depress the pedal 1/3 to 1/2 and hold, then engage the starter. (sorry if all that is superfluous)

I'd say check the carb diaphragms as well, but you'd have stumbling and such while running if they were bad. So I'm thinking needle valve(s).
Brent B

Why would they stick when warm, though i like your thinking
DON KELLY

Don - not when warm, but cooled off and things contract a bit.
Brent B

After listening to all your answers and comments, I have decided to rebuild the carbs. This should resolve any sticking, leaking and give me a good education on Stromberg carbs.

Thanks for all your input,
Ken
L Caya

Ken,
A word...I've been in the midst of rebuild of my carbs for the last several weeks (it just takes me longer than others). FYI, here's what I've done. After complete disassembly, I powdered coated the exterior, selectly removing and masking some components. I purchased the complete rebuild kit from TRF, and am replacing all except the piston spring, the bottom plug and some exterior screws. I suggest you consider purchasing new screws for the top and bottom unless your's are in much better condition than were mine. I also recommend that you thoroughly clean the interior of the carb in ALL areas especially the various vents and tube connections. I've used long handled "Q" tips, copper wire brushes, lacquer thinner, acetone and alcohol at various times. Soaking the whole thing in lacquer thinner may do a great job and need nothing else, but I found that I needed to also apply some focused elbow grease to remove lacquer deposits here and there. Where I could, I also polished areas that will see the flow of fuel and air. I had no small amount of difficulty removing the needles. Destroyed one and the other is not really savageable, not that I was going to reuse either, but mine had frozen in place and took an inordinate effort to finally break free. Since your's has been running, you're not apt to have this problem. My engine has not run in 20+ years. Do one carb at a time so you'll have a go by to put back together!! Get Buckeye's instructions and TRF's Blue Book parts blow up. Have fun.
db
Doug Baker

If you're going to do a "serious" overhaul then replace the throttle shafts, too. Those get worn over time (being a softer material than the steel bushes) and can be a source of a vacuum leak even with new rubber seals.
Brent B

Ken, If you can swing it Jeff @ http://www.paltech1.com/index.html does a great job at this.
Not only that they will look pretty too.
DON KELLY

db, Brent, Don,

As always, apprieciate the input and will consider all the above. I'll post if I have any questions or issues.

Ken
L Caya

This thread was discussed between 20/06/2011 and 24/06/2011

Triumph TR6 index

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