eavega
Lieutenant
- Joined
- Apr 29, 2008
- Messages
- 1,377
Hi all
So far I have had a month and a half of trouble-free boating. I had a little problem starting the motor this weekend on the last move of the day from the courtesy dock to the trailer (wouldn't start on its normal first or second bump of the key. Took about three ten-second cranks to get it started again, but once started ran at idle speeds without issue), so I hooked up the muffs on the driveway just to verify that I hadn't lost spark or some other issue had cropped up. I couldn't recreate the problem on the driveway so I am chalking that up to some kind of one-off condition for the moment. Anyway, on the muffs I noticed that my idle RPMs were closer to the 1400 RPM range than the 1000 RPMs that it should be. Timing at idle is at TDC, so I am hesitant to mess with any of the timing mechanisms to get it to idle down. The idle adjust screw doesn't do a thing to allow me to idle down. It does allow the idle to come up, though. I did notice that if you back out the idle adjust screw, you can push the yoke further back, but I didn't do that as that would cause the timing to go out on the motor. I put the idle adjust screw back to where I found it, and the motor is happily idling at 1400 RPMs with the timing at TDC. Link n synch was done on this motor last year when I rebuilt and made some adjustments to the carburetors. Should I just leave well enough alone and accept that the motor idles high or the tach may be a little off (note that at WOT my tach is reading 5K RPMs so if it is a little off, I am still in an acceptable range for my motor)? Should I re-do the link n synch just to be sure everything is set properly?
UPDATE
Today I did some more testing on the motor. After verifying compression and spark, I pulled out the optical tach and verified that my tachometer was correctly reading the idle speed of 1400 RPMs. Next, I broke out the timing light, and Joe Reeve's timing adjust method, and noted that the motor was reading about 3 degrees off of what it should be (Timing for this motor is 17 degrees, by Joe Reeve's method, the timing light should show 13 degrees, timing was actually 16 degrees). I have the timing adjusted to read 13 degrees now with timing fully advanced.
THE GOOD - The motor now idles at 1100 RPM on muffs.
THE BAD - the idle timing is now showing off of TDC by a few degrees (off the scale on the flywheel, but I would estimate about 2-3 degrees)
The motor idles very steady at 1100 RPM, and doesn't sound any worse (or better) than it used to before trying to adjust the timing.
Joe Reeves says that the idle timing should work itself out. Should I leave it as is until I verify that the motor is running at its proper 17 degrees at WOT even if the idle timing seems to be off? Is there anything else I should do before putting it on the lake and seeing if it runs any better or worse? Joe spells out the dangers of running with timing adavnced too far (pre-ignition) am I doing anything but possibly losing some power by having the timing retarded too far?
Any advice or suggestions would be greatly appreciated.
Rgds
So far I have had a month and a half of trouble-free boating. I had a little problem starting the motor this weekend on the last move of the day from the courtesy dock to the trailer (wouldn't start on its normal first or second bump of the key. Took about three ten-second cranks to get it started again, but once started ran at idle speeds without issue), so I hooked up the muffs on the driveway just to verify that I hadn't lost spark or some other issue had cropped up. I couldn't recreate the problem on the driveway so I am chalking that up to some kind of one-off condition for the moment. Anyway, on the muffs I noticed that my idle RPMs were closer to the 1400 RPM range than the 1000 RPMs that it should be. Timing at idle is at TDC, so I am hesitant to mess with any of the timing mechanisms to get it to idle down. The idle adjust screw doesn't do a thing to allow me to idle down. It does allow the idle to come up, though. I did notice that if you back out the idle adjust screw, you can push the yoke further back, but I didn't do that as that would cause the timing to go out on the motor. I put the idle adjust screw back to where I found it, and the motor is happily idling at 1400 RPMs with the timing at TDC. Link n synch was done on this motor last year when I rebuilt and made some adjustments to the carburetors. Should I just leave well enough alone and accept that the motor idles high or the tach may be a little off (note that at WOT my tach is reading 5K RPMs so if it is a little off, I am still in an acceptable range for my motor)? Should I re-do the link n synch just to be sure everything is set properly?
UPDATE
Today I did some more testing on the motor. After verifying compression and spark, I pulled out the optical tach and verified that my tachometer was correctly reading the idle speed of 1400 RPMs. Next, I broke out the timing light, and Joe Reeve's timing adjust method, and noted that the motor was reading about 3 degrees off of what it should be (Timing for this motor is 17 degrees, by Joe Reeve's method, the timing light should show 13 degrees, timing was actually 16 degrees). I have the timing adjusted to read 13 degrees now with timing fully advanced.
THE GOOD - The motor now idles at 1100 RPM on muffs.
THE BAD - the idle timing is now showing off of TDC by a few degrees (off the scale on the flywheel, but I would estimate about 2-3 degrees)
The motor idles very steady at 1100 RPM, and doesn't sound any worse (or better) than it used to before trying to adjust the timing.
Joe Reeves says that the idle timing should work itself out. Should I leave it as is until I verify that the motor is running at its proper 17 degrees at WOT even if the idle timing seems to be off? Is there anything else I should do before putting it on the lake and seeing if it runs any better or worse? Joe spells out the dangers of running with timing adavnced too far (pre-ignition) am I doing anything but possibly losing some power by having the timing retarded too far?
Any advice or suggestions would be greatly appreciated.
Rgds
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