[TR] Recalcitrant TR3B Engine

Bud Rolofson levilevi at comcast.net
Sun Mar 4 12:45:58 MST 2012


I'd guess Jonas and Randall are on to something with the intake  
manifold not being flush.

If after cranking the engine the plugs aren't wet, and if the float  
chambers are full as you said, then your mixture isn't getting to the  
cylinders.  Can you feel gas at the bottom of the intake manifold or  
smell excess gas or feel a gap for that matter?


Bud Rolofson

71TR6 CC57365 (Good 6)
66TR4A CTC57806 (The Wreck-Almost parts)
66TR4A CTC57529 (The Project)
71F-250 Camper Special (Triumph Support Vehicle)
Z-50A Hardly Davidson 1977 Honda Mini-Trail Bike (Triumph Pit Bike)
levilevi at comcast.net



>>
>
> Can you keep it running on the starter fluid?  Or does it just fire  
> once or
> twice and not actually start?
>
> If the former, then it is clearly not getting enough fuel.  Try  
> giving it
> more choke.  If that doesn't work, drain and replace the fuel.   
> Modern fuel
> spoils quickly when stored in a vented tank (like the TR3 tank).
>
> If the latter, I would suspect the timing is 180 out.  BTDT
>
>>  b. Verified valve gaps set to .012
>>  e. Point gap set to  .013.
>
> Is there some reason you aren't using the factory values (.010 and . 
> 015
> respectively)?  I doubt that is the problem, I'm just curious.
>
> Another possibility based on your report would be a largish intake  
> vacuum
> leak, like maybe the intake manifold is not correctly seated against  
> the
> head.  It can sometimes catch on the alignment pins and stick out at  
> the
> bottom where it is hard to see.  Or if the head has been machined to
> increase compression, the manifold may catch on the edge of the  
> block and
> cause the same problem.  I have also seen problems caused by  
> tightening the
> nuts on the connection between intake and exhaust, before having both
> manifolds clamped to the head.  (I leave those nuts off on my TR.)
>
> -- Randall  


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