----- Original Message -----
From: "Ed Purcell" <epurcell05@comcast.net>
To: "TR List" <triumphs@autox.team.net>
Sent: Wednesday, June 13, 2007 1:39 PM
Subject: Re: [TR] TR4 Cutting Out Under Load
> ----- Original Message -----
> From: "Peter C" <peter@nosimport.com>
> To: "Ed Purcell" <epurcell05@comcast.net>; "TR List"
> <triumphs@autox.team.net>
> Sent: Wednesday, June 13, 2007 11:27 AM
> Subject: Re: [TR] TR4 Cutting Out Under Load
>
>
>> Ed, that is a typical sign of a high tension ignition breakdown. Suspect
>> ignition rotor cracked, cap has cracks, coil wire loose.
>> Peter C
>> ==
>> At 09:36 AM 6/13/2007, Ed Purcell wrote:
>>
>>>Hi Listers, I have a late TR4 with a fairly new Pertronix distributor.
>>>It ran fine for a while after installation. I attempted to adjust the ZS
>>>175's due to a rough idle with poor results. I then reseated the jets
>>>and backed off three turns per the manual. The car now revs fine in
>>>neutral. On the road it cuts out. The higher the gear, the lower RPM the
>>>miss begins. Hence the greater the load the poorer the performance. All
>>>ideas appreciated. Thanks,
>
> Thanks Peter and Bob, And for anyone else pondering this, I just put the
> old points distributor back in and the symptoms did not change. They say
> the carbs are usually not the problem, but it sure looks like mine are
> messed up. To reinterate, I have excellent idle and operation at low
> RPM. Cutting out starts @ about 2K under load. I can nurse it up to about
> 3K max. Also cuts out worse up hill. Thanks again.
>
> Ed Purcell
Roland, Skip, Randall, Jim, Peter, Bob, and list, My next move was to
replace the coil. No change resulted, but as I replaced it I noticed the
slightly weeping seal on my fuel pump and thought that a weak pump would
cause my symptoms. I installed an available spare pump (a most trying job)
which to my major disappointment did not help my problem. So finally to the
carbs I went. Basically the problem was that the air valve (piston) on the
rear carb was not dropping down to what I think is the "starter bar" in the
diagram. A reminder that these are ZS 175 carbs. Instead of the clunk when
the piston was dropped, it stopped almost a quarter inch above the bar that
raises when the choke is pulled. I raised the jet and then loosened the
capture nut and carefully centered the jet. I achieved the clunk, but the
piston needs to be cleaned. I now have a much better running car. The
problem is corrected, but I have some fine tuning to do on the carbs.
Now I will speculate on how I managed to get into this mess. I think that
at some time in the past my choke was misadjust or got gummed up to the
point that the starter bar was not lowering completely when I pushed the
choke in. I then did the adjustments to the carbs in that condition and ran
that way for an unknown period of time. When I recently tweaked the carbs
due to a rough idle I must have lowered the bar at the carbs. The piston on
the rear carb would fall to where the bar had been, but now the bar is lower
which caused the problem in the subject.
I would have thought that the piston problem would have caused poor
performance at low RPM. I am not fully content with this issue yet, but I
have related it as best I can recall. This will be my last update unless
there is a great revelation of some type. Thanks to all again.
Ed Purcell
Clinton, TN
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