RE: [omc-boats] problem solved

Tom K:
 
Thank you for the time you took to relay the process and your success.
The 'lessons learned' part of this forum is great.
 
Again thank you,
 
David Avedesian
Silver Spring, MD
 
-----Original Message-----
From: owner-omc-boats@... [mailto:owner-omc-boats@...]
On Behalf Of Thomas Klauber
Sent: Wednesday, September 01, 2004 10:49 PM
To: omc-boats-digest@...
Subject: [omc-boats] problem solved
 
Some of you may remember my post several weeks back about my 69 Rogue V8
that had no power on acceleration above 1000rpm. I think I found and
solved the problem. I first got a little delay from hurricane Charley
that passed right over Marion,SC! First, I replaced points, plug
wires, condensor,coil,rotor and distributor cap. That not solving the
problem I kept the old parts which should still be useful. I rebuilt the
carburetor. No luck. I checked the carb. to intake manifold gaskets.
Nope! About this time I ran across something in one of my manuals ( I
think it was the Clymer ) on vacuum testing. I had not done this and
gave it a try. First I got online and learned about engine vacuum and
how to test it. I went to the NAPA store and bought a plug that screws
directly into the hole along one of the runners of the intake manifold
to draw a true vacuum reading. This plug had a nipple end that I plugged
my vacuum gauge to. These gauges are fairly cheap. I cranked the engine
and the needle was swinging wildly between 0 and about 15. It seemed to
read "late valve timing" - I figured what does that mean? Back to the
internet for a lesson on engine valve timing. At this time I was
thinking - did the timing gear get off somehow? Anyway I decided to
adjust the valves one more time. A mechanic friend of mine said that
most people turn the valves down one quarter rather than the full turn
as described in the literature. I went in to recheck the valves. I
pulled the odd valve cover off first and proceeded to back off the
valves to 1/4 turn. I would loosen till they chattered and then slowly
tighten to 1/4. I finished the odd half then went to the even side
beginning with #8 then #6 and at this time the vacuum needle still
hadn't changed. When I did #4 the needle leveled out and by the time I
had done the last valve of cylinder #2 the needle was steady and up into
the normal range and you could tell a noticeable improvement in idle. I
still don't quite understand what went right but I will use the vacuum
gauge more often when I test and tune. I also did not use any of the
ports off the carb. to test the vacuum which I think may not give an
accurate reading. They say you can use the rear port that usually hooks
vacuum to a PC valve or to a brake master cylinder but I had no such
port on the back of the Roch. 4 barrel. Maybe because it is a marine
carb. or pre-emission model? The more I worked with these valves the
more I came to respect them and the effects they can have when out of
adjustment. I don't know how I got them overtightened initially but
suspect that I was trying to go too fast and not allowing them to bleed
down during adjustment. Anyway I hope this will help someone someday
when they get a similar problem. Now if I can get to the river before
hurricane Frances hits his weekend! Tom K.
Received on Wednesday, 1 September 2004