PDA

View Full Version : TR2/3/3A 60 TR3A Will not run above idle speed, help!



Tinkerman
10-12-2012, 08:40 AM
I just got my engine running, this is a totally rebuilt engine. It starts and runs. It was running rough at first but got it smoothed out and it now starts quickly and runs well. HOWEVER I cannot get it to run above the idle speed. Checked all the usual suspects. Here is what's happening:
1. Put about 1/2 gallon of gas in it.
2. While it is running, when I put my hand in front of the carb I can feel a fine mist of fuel coming out of the carb.
3. I sent the bodies off to the fellow on Long Island and had him put in new throttle shafts and of course he re-bushed them.
4. I rebuilt the carbs. I have re-built many carbs over the year, including a set of SU's from a 52 Jag sedan, but that was many years ago. I'm out of my depth here and need some trouble shooting help.
QUESTIONS:
1. Is it a Carb problem?
2. Is it a fuel problem?
3. Is it a pump problem?
4. Is it an operator problem?
Thanks, Tinkerman

BustedKnuckles
10-12-2012, 09:36 AM
Who rebuilt the engine?

Can we assume that all the relevant pieces are in correct time to each other?

NutmegCT
10-12-2012, 10:03 AM
Dick - when you pull out the choke knob, does the idle speed go up? Does the idle speed drop when you push the choke knob back in?

Tom

sp53
10-12-2012, 10:47 AM
The good news is that it runs. Check and see if the carb link that keeps both carbs working together has not slipped lose. It sounds like fuel to me. In addition, I look at the plugs a lot on a new engine to see if they are not fouled.

DanB
10-12-2012, 12:11 PM
How is the timing set?

Tcraftdriver
10-12-2012, 06:33 PM
A fine mist of fuel coming out of the carb while the engine is running? Where is it coming from?

If you can feel it on your hand, is your hand in front of the venturi? Seems like there should be a small vacuum there. Could something be pressurizing the intake manifold at higher RPM than idle? Does the engine idle smoothly or could an intake valve be not fully closed or sticking partially open?
Have you done a compression check?

Are you using an electric fuel pump?

Is fuel leaking out of the carbs when the engine is running besides that fine mist you feel when the engine is running?

Have you checked the timing and the distributor timing with respect to it being in the proper position when number 1 is at top dead center? Where does the rotor point when number one is at top dead center? Could the distributor be off one tooth? This might cause enough of a timing problem the engine won't run above idle if the spark is too far retarded.

TR3driver
10-12-2012, 10:11 PM
2. While it is running, when I put my hand in front of the carb I can feel a fine mist of fuel coming out of the carb.

Sounds like cam timing to me. Might be a stuck valve or really tight valve adjustment; maybe even a radical cam. But given that it is a fresh rebuild, I'll bet the cam timing is wrong.

One way to check:
Turn the engine until both valves on #4 are partially open. Set the lash for both valves on #1 to .050". Turn the engine forward through one full turn, stopping when the TDC pointer lines up with the hole. (If you go past, you must back up and try again, don't turn the engine backwards to line the marks up.) Now check the clearance on both #1 valves. They should be very nearly equal, or the intake a little bit tighter.

Afterwards of course, reset the lash to the usual .010".

Got_All_4
10-12-2012, 10:27 PM
I had that same problem. With my 3 and one of the rockers was too tight. Same exact symtoms. Readjusted the valve lash and life was good. Hope yours is as easy.

Tinkerman
10-13-2012, 11:59 AM
My thanks to all of you for the good and interesting thoughts on my problem. I will try to answer as many questions as I can.
Some info on what has been done. The engine is a relative stock engine with a mild street cam, 87mm pistons, and a ported and relieved head(as much as could be done. Machine work was done by a competant local machine shop.
I rebuilt the engine. It was timed to (I think) 12 degree BTDC by me using a degree wheel. It could be 12 degrees ATDC. I can't remember and can't find my notes(sigh). Yes you can assume that all the relevant parts are in correct time.
I have not looked at the plugs, nor have I checked under the valve cover(to be done this afternoon). The carbs were rebuilt by me but I bought new throttle shafts and had the carb body re-bushed by Joe Curto.
The fine gas spray comes from the air input end of the venturi. I have not fiddled with the choke, except to get it started. I have not done a compression check. I am using a standard primer type fuel pump. The carbs are not leaking.
I am in communication with Joe Curto. I have checked the allignment of the vent holes, they are correct. I have done a piston drop test and find that it is dropping faster than it should which Joe feels is an indicator that I have a vaccum problem. We are working on that.
Running out of space, thanks for all the comments.
Will let ya'll know how it comes out, Dick

Tinkerman
10-15-2012, 04:16 PM
Checked valve lash Saturday found a mixed bag of adjustments. Not real sure how that happened. Set them all to .010, helped a bit but did not solve the problem. Will make another test tomorrow. It is running real smooth how. After tomorrow's test we will await the arrival of parts from Joe Curto.
Cheers, Dick

Brinkerhoff
10-15-2012, 07:51 PM
Dick , it could be a number of things ,but the cam timing would be the first to verify like Randall says. An engine needs to be mechanically in time to work as an efficient air pump . How did you set up the cam timing? Do you have the shop manual? Kevin ( fixer of many things British)

Got_All_4
10-15-2012, 08:29 PM
There is something that is causing a blow back through the carbs. I can't think of no other reasone to have a mist coming out of a carb with the engine running. I would do that compression check next to see if you have a bent valve or one not seating properly. Hope that's not the case.