Starting chain adjustment

buoy

.
Jan 26, 2008
6
Hunter 37' Cutter Lake Lanier
I have a 1980 Hunter 37’ cutter. The boat is powered by a Yanmar 3QM30. The starting chain has broken. I went to a bicycle shop to replace the chain. Exact size but is sloppy, needs to be adjusted. I looked in manual, but no mention of adjustment.

Is there anyone who has replaced or adjust the chain?
Thanks.
George
 
Jun 8, 2004
912
C&C Frigate 36 St. Margarets Bay, Nova Scotia
Wow! have you ever hand-cranked the 3QM30? If so, you're a better man than me... I guess it would be useful turning the engine over for maintenance, etc...if I even had the crank handle - did yours come with one? I mean, I like the idea of being able to start the engine without battery or starter motor, but I remember hand-cranking old 3-cylinder lifeboat engines for my MED certificate and it was a bear! All this to say I have not replaced or adjusted mine. I don't believe there even is an way to adjust it. Mine has a fair bit of slack...
 

buoy

.
Jan 26, 2008
6
Hunter 37' Cutter Lake Lanier
I don't know about half link..... But will look at it.
 

buoy

.
Jan 26, 2008
6
Hunter 37' Cutter Lake Lanier
Jim,

How much slack is in your chain? I have too much slack. May need to remove a link?
 
May 20, 2016
2,992
Catalina 36 MK1 94 Everett, WA
I've hand cranked Volvo's before - not too bad just don't let the compression release lever slip to closed while the crank is inserted. I've had one start on me with the handle stuck in the engine - talk about vibration!!!
 
Jan 19, 2010
948
Catalina 34 Casco Bay
guess that's better than starting with a blank 12 ga shot gun shell.....
 

mm2347

.
Oct 21, 2008
238
oday 222 niagara
I have only seen the shotgun blank used in starting an airplane engine in the movies. Can imagine being in an engine compartment in the bowels of a sailboat and "pulling the trigger"!
 
Jun 8, 2004
912
C&C Frigate 36 St. Margarets Bay, Nova Scotia
Jim,

How much slack is in your chain? I have too much slack. May need to remove a link?
From memory, there is between 1/4" and 1/2" deflection at mid point between the cogs. Having never hand cranked my 3QM30, I can't say if that is too much. I think as long as the chain doesn't come off the cogs, slack isn't a problem. When turning over the engine, only one side of the chain draws tight. And there is a roller clutch on the engine gear, so the chain doesn't move when the engine is running. According to the manual, there should be 67 links in your chain.