Author: "gptyler_1999" <gptyler@...> Time: Tue Aug 13, 2002 5:21 am PDT Link
I have a perplexing problem with my Lycoming 0320 engine that has
occured ever since I have had it. It ever so briefly, looses
power,hesitates or quits, just for an instant and then continues to
run normally. When I first got it it happened most frequently soon
after take-off in conjunction with throttleing back. Then for a long
time it didn't happen at all. Lately it has been occuring while in
normal flight at cruise. I have never had it happen more than once
in any single flight. I have had it serviced by a mechanic who has
worked on the float and jets, but in truth he has told me that he
sees nothing wrong with the carb. It is a standard factory issue
carb. When it happens it sure get my attention in a hurry and just as
quick it is over. I guess I can live with it but I don't like it and
keep wondering if it is forcasting something more permanent. Any one
have any ideas? George Tyler 226DG
Author: Doug Gray <douggray@...> Time: Tue Aug 13, 2002 7:05 am PDT Link
gptyler_1999 wrote:
> I have a perplexing problem with my Lycoming 0320 engine that has
> occured ever since I have had it. It ever so briefly, looses
> power,hesitates or quits, just for an instant and then continues to
> run normally. When I first got it it happened most frequently soon
> after take-off in conjunction with throttleing back. Then for a long
> time it didn't happen at all. Lately it has been occuring while in
> normal flight at cruise. I have never had it happen more than once
> in any single flight. I have had it serviced by a mechanic who has
> worked on the float and jets, but in truth he has told me that he
> sees nothing wrong with the carb. It is a standard factory issue
> carb. When it happens it sure get my attention in a hurry and just as
> quick it is over. I guess I can live with it but I don't like it and
> keep wondering if it is forcasting something more permanent. Any one
> have any ideas? George Tyler 226DG
I can understand your concern.
I'm certain I cannot answer the question but I have some questions:
What fuel are you using?
What methods do you use to lean the engine?
Do your plugs show any evidence of Lead accumulation?
Engine service history?
Could be lead. I have seen a huge accumulation of lead on plugs and even as
solid lumps inside the cylinders (cleared by removing the bottm plugs and
turning the prop) after engines are run at low power full rich settings
(precationary search training) , I could imagine a momentary hesitation as
this is 'passed'. Hot engine = vapourised lead.
Alternative suggestion is a sticking valve. Refer Lycoming website for
extensive discussion on this topic. Again operating habits contribute.
Doug Gray
Author: "Garbroco" <GARBROCO@...> Time: Tue Aug 13, 2002 7:05 am PDT Link
GEORGE,
MY RV-4 (N63DG) HAD THE SAME PROBLEM FOR THE 8 OR SO YEARS I FLEW IT.
RIGHT AFTER LEVEL OFF AND THROTTLING BACK TO CRUISE, IT WOULD BURP OR HESITATE. AFTER A WHILE IT DIDN'T BOTHER ME, BUT MY PASSENGERS WOULD ALWAYS ASK ABOUT IT AND INITIALLY IT REALLY GOT MY ATTENTION.
ORIGINALLY FLEW WITH A ALMOST RUN OUT 150 HP O-320 - DID IT THEN, ALTHOUGH NOT ALL THE TIME. ALSO DID IT AFTER THE ENGINE WAS OVERHAULED TO 160 HP SPECS. FUEL SYSTEM WAS AS PER THE PLANS. ORIGINALLY HAD THE STRAIGHT IN (NO FILTER) AIR BOX AND LATER WAS CHANGED TO VAN'S FILTERED BOX. NO DIFFERENCE EITHER WAY.
CHECKED EVERYTHING, UP TO AND INCLUDING PUTTING A NEW CARBURATOR, NEW MAGS, AND IGNITION HARNESS ON IT. THERE IS A SERVICE BULLETIN FOR CERTAIN O-320'S FROM LYCOMING REGARDING HESITATION ON THROTTLE APPLICATION - AS I RECALL IT TYPICALLY WAS FOR PA-28'S (CHEROKEE'S) AND INVOLVED INSTALLING A NEW VENTURI. I HAD THIS DONE AND IT DID NOT SOLVE THE PROBLEM.
ALMOST HAS TO BE FLOAT LEVEL OR SOMETHING RELATED.
NEVER DID FIGURE IT OUT.
GO FIGURE.
DAVE GEHLE
HEBER SPRINGS, ARKANSAS
RV-4, RV-6A
----- Original Message -----
From: gptyler_1999
To: RV-6and6A@yahoogroups.com
Sent: Monday, August 12, 2002 6:55 PM
Subject: [RV-6/6A] Engine hesitation
I have a perplexing problem with my Lycoming 0320 engine that has
occured ever since I have had it. It ever so briefly, looses
power,hesitates or quits, just for an instant and then continues to
run normally. When I first got it it happened most frequently soon
after take-off in conjunction with throttleing back. Then for a long
time it didn't happen at all. Lately it has been occuring while in
normal flight at cruise. I have never had it happen more than once
in any single flight. I have had it serviced by a mechanic who has
worked on the float and jets, but in truth he has told me that he
sees nothing wrong with the carb. It is a standard factory issue
carb. When it happens it sure get my attention in a hurry and just as
quick it is over. I guess I can live with it but I don't like it and
keep wondering if it is forcasting something more permanent. Any one
have any ideas? George Tyler 226DG
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Author: "rv7boy" <rv7boy@...> Time: Tue Aug 13, 2002 9:22 am PDT Link
George,
You might try asking this question in the Lycoming Engine Yahoo
Group. You will probably get more responses there.
Don Hull