J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Adjusting Throttle & Transmission Controls

Are there any standard set up procedures for adjusting the throttle & transmission cables? It feels like the throttle is advancing before the transmission shifts into gear resulting in a thunk from the propellor. My first guess is to shorten the throttle cable to give the transmission time to engage. Any pointers would be appreciated.

depends on how much of a thunk you are getting. but they do thunk when the blades hit their stops. and idle is ~ 750?

Check out the following link to the Ops & Maint manual on this site;
http://j30.us/files/yanmar-manual.pdf

Read pages 12-15. Most likely your operation lever assembly at the clutch/transmission case needs adjusting or is too worn to be adjusted properly. You might also loosen the throttle cable at the engine end to slightly delay the throttle action.
Good Luck,

OK Thanks for the link. My transmission is new. The robbers at the yard advised me the control lever needed to be replaced. I'll adjust it first.

Regards,
Rob

Rob - when they replaced the transmission, did the cables get replaced too? You'll notice that the transmission shift lever has a spring loaded dashpot as shown in the link Al referenced above. The dashpot helps maintain positive positioning of the shift lever for both ahead and astern. It is important that it is setup correctly. If the cable does not have the dashpot, you may have a problem insuring the transmission is engaged fully (e.g. shift lever out of transmission may not be in the correct position).

It is highly unlikely that the shift lever needs to be replaced. The lever should have a spring loaded detent ball that you can feel engage for the ahead and astern positions. As the lever is rotated further, the throttle cable starts to get pulled. This should be symmetrical for ahead and astern.

Just a follow up after a trip to the boat this morning. The transmission does engage first before any throttle movement takes place. There is no dash pot at the transmission. It is a solid brass piece on the end of the cable that attaches to the transmission shift lever. I lowered the idle per VJ and will move the lever slowly.

Us old timers used to have to double clutch some of the now older antique cars. this isn't quite so bad ... don't have to move leaver slowly out of gear ... but its good to stop in neutral a couple of seconds before changing direction. then advance a small bit to get the thunk ... then wham it once the blades have hit the stops.

in an emergency you do what you have to do. remembering that you probably need double revs to equal prop power in rev.

Has anyone heard of a clutch slipping / chattering situation where light finger pressure on the lever coming out of the KM2A transmission (2GM engine) stops chatter and greatly increases shaft speed, or where replacing the spring in the "dashpot" causes the same improvement? I have already made some improvement by switching to the 52mm radius (inner) hole and the outer hole on the cockpit controls. I suspect that this is countering some, but not all of the wear in the cones and dashpot components, and I'm confident that the changes made so far are not causing undue pressure on the shifter fork. However, I suspect that the next time out will show that I still have slippage.

TIA,

-Chris

Chris,

You should adjust the spring/dashpot per the Yanmar manual page 14. My guess is if it has been misadjusted, it will contribute to clutch wear/glazing the cone.

Update: The real fix - deglazing - is now complete and the clutch is now working well. The procedure, well described on cruiserforum.com and Bill's site, was pretty easy. The only trick was to pull the gear off the spline end first, then remove the nut and other gear. Ready for next season!