Choke valve position cold engine

YOBE

Seaman Apprentice
Joined
Mar 12, 2019
Messages
41
Hi,

Today I started the engine, mercruiser 165HP from ‘70, for the first time since I bought the boat.
Carb has been rebuilt. And still operating the choke manually
I did put the choke in full closed position. Pulled the throttle 2x to inject some extra fuel.
Engine started almost immediately (me happy!!). After about 45sec I did shut it down as no cooling water was connected.
Before calling it a day I wanted to start it one more time for a few seconds.
Again had choke in closed position.
BUT I couldn’t get it running again. Tried with some extra fuel, no solution.
Only after slightly opening the choke valve it started again.

Question:
Should I better set the choke slightly open as a default position?
Or is there another reason for the starting problem that I “bypassed” by opening the choke slightly

PS: during the few seconds I let it run, it was obvious: as soon as I forced the choke to “full close” it would start to stumble towards stopping.
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
6,756
Hi,

Today I started the engine, mercruiser 165HP from ‘70, for the first time since I bought the boat.
Carb has been rebuilt. And still operating the choke manually
I did put the choke in full closed position. Pulled the throttle 2x to inject some extra fuel.
Engine started almost immediately (me happy!!). After about 45sec I did shut it down as no cooling water was connected.
Before calling it a day I wanted to start it one more time for a few seconds.
Again had choke in closed position.
BUT I couldn’t get it running again. Tried with some extra fuel, no solution.
Only after slightly opening the choke valve it started again.

Question:
Should I better set the choke slightly open as a default position?
Or is there another reason for the starting problem that I “bypassed” by opening the choke slightly

PS: during the few seconds I let it run, it was obvious: as soon as I forced the choke to “full close” it would start to stumble towards stopping.
it may have been flooded or overly rich. Opening the choke and throttle will help clear a flooded or rich condition.

when operating properly the choke will go fully closed but pops open a bit when the engine starts, then slowly opens more to full open when the engine warms up.

Get it running and warmed up -set the dell, timing, set the idle speed and mixture then set the choke per the factory manual. You dont need the choke much unless its cold out
 

YOBE

Seaman Apprentice
Joined
Mar 12, 2019
Messages
41
Right, I also noticed that the choke indeed tried to pop open a bit when the engine started even when I pushed it closed it really pushed back to slightly open.
 

YOBE

Seaman Apprentice
Joined
Mar 12, 2019
Messages
41
it may have been flooded or overly rich. Opening the choke and throttle will help clear a flooded or rich condition.

when operating properly the choke will go fully closed but pops open a bit when the engine starts, then slowly opens more to full open when the engine warms up.

Get it running and warmed up -set the dell, timing, set the idle speed and mixture then set the choke per the factory manual. You dont need the choke much unless its cold out
Sorry for my lack of knowledge. What you mean with “dell”?
So before starting to “adjust” settings it’s better to get it to temperature first?
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
6,756
Sorry for my lack of knowledge. What you mean with “dell”?
So before starting to “adjust” settings it’s better to get it to temperature first?
Typo dwell, ignition points dwell. Set dwell then timing.

yes any tune up is done once it gets to operating temp. Get a factory service manual for your engine. Merc manuals have great detail on specs and procedures. If you have a modicum of mechanical knowledge a manual will help dramatically
 
Top