RPM'S drop drastically when trans. engaged

[Roy]

When cold no amount of throttle feathering will prevent the engine from stalling and cutting off when shifting into gear. After warm up this doesn't happen, but when idling along in gear then shifting to neutral, engine rpm's go way up. Something seems to be dragging the engine down. The shaft log is ok. Top speed is down to about 5.6K use to get 6.5 which is not unusual for a Pearson 30. The transmission was adjusted some time ago but I don't recall this happening right after.

[Dave Neptune]

Trans??

Roy, it is a bit normal for an engine to be fussy until warmed a bit. If it has been slowly getting fussier it could just need a tune. How long since a tune or timing adjustment? You could try to give the idle adjustment screw on the top of the carb a 1/4 turn in and see if it acts better when cold, sometimes a bit richer mix will help.
Are you using points or an electronic type ignition?
The prop and bottom being a bit dirty could be the reason the speed has dropped. Have you tried to rotate the shaft by hand in nutral?
How many RPM's are you talking about?

Dave Neptune

[joe_db]

My boat has done this for a long time. It makes it kind of a pain to operate, since you had to finesse the gear shift and throttle with every shift.
Replacing the carb helped quite a bit, but it isn't totally solved. I suspect it is/was a mix of a clogged idle circuit* and some water ingress from a bad head gasket/hole in block/leaking manifold bolt/or ??? that allows water to get in at slow speeds only.

Symptom of a clogged idle circuit: Hair-trigger throttle. Below a certain RPM the engine just dies.

[Baltimore Sailor]

I'd have to go with the clogged idle jets, too. Back in '07 when I got my A4 I also had to finesse the throttle/shifter to keep her from stalling. I ended up replacing the carb, and after a bit of adjustment I can throttle right down to idle and she sits there solid as a rock at about 800 RPM.

I also put in the adjustable main, but I had the good idle a season or so before that. I'm just a control freak, and the more things I can adjust the better I like it.