Velvet Drive shift cables

Hi Everyone
New to the forum. Ex sailor who just purchased a 1984 Mainship 40 DC with twin Perkins 6.345 & velvet drives. My port shifter at both helm stations is difficult to shift so I am beginning my troubleshooting journey.
On my visual inspection, I noticed that the transmission on the port side has one shifter cable while the starboard transmission has 2 shifter cables . Does anyone know why starboard has two cables vs. one for port?

Thanks for your help
Jim

Stiff shifting is almost always caused by a failing cable. But it’s still prudent to disconnect the cables from the shifters and make sure the shift levers themselves move freely. Normally, the shift cable goes from the transmission to the lower shifter, then a second cable goes from the lower shifter to the upper shifter. It should be fairly easy to look at them and at least see if they head in those directions. As far as the double cable on the STB transmission, I’m not sure, it may be that someone along the way chose to run directly from the transmission to each shifter, or it could be an auxiliary cable that is used for some other purpose. Again, they’re not hard to follow. Perhaps you can trace where they go?

Ken.

For synchronizers is my guess.

Agree that it is likely stiff cables. You might try unhooking the upper cables and see if it is easier. If it is then it is the upper cable. Another thing to try that may or may not help is to lubricate the cables. There used to be a process on how to lubricate shift cables using Marvel Mystery oil on the Trojan boat owners forum. Try a google search using those terms and see if it is something you want to try.

I found the directions. I have never tried this so I can’t say it works or not but it may save you from replacing the cables, at least for a while.


Directions for a Throttle and Shift Cable Oiler


You need a foot and a half of 3/8 ID reinforced plastic hose from Lowes, a tire valve, three hose clamps, a tire pump or small 12 volt air compressor with a gauge, and some MMO (Marvel Mystery Oil).

Shave the tire valve down and clamp it in one end of the hose.

1. Remove the fittings from one end of the cable.

2. Put 3 inches of Marvel Mystery Oil in the hose for every 20 feet of cable length.

3. Double clamp oil filled hose over cable.

4. Apply and maintain 50 PSI of air to the tire chuck. DO NOT EXCEED 50 PSI.

5. It will take 10 to 30 minutes for oil to appear at the other end, then your done. Have rags to catch the oil if your in a sensitive area.

I suggest safety glasses just in case somethings blows apart, but I have never had a problem. My save rate on cables is about 75%. I did all my cables ever

I would agree with failing shift cables. I would disconnect the upper helm but at the lower helm. If the upper helm cycles smoothly then you can rule out the upper cables. If the lower cables cycle smoothly then you have a shifter adjustment issue. My guess, one of the helms will continue to not shift smoothly.

I have the same engine and transmission. I also experienced the same problem which the cause in my case was a bent metal end of the shift cable where it was on the transmission, between the end of the cable and to the linkage. I figured out the cause was a mechanic who did the oil change, stepped on the cable end, bending it enough to make it virtually impossible to shift. Replaced the cable and all worked smoothly again.

Typical control cable installations are either "parallel" or in "series." The cable oiler band aid rarely works, and the recommended fix is to replace the cable(s)
Engine and gear controls are nothing to fix by a half measure

I would do the opposite. First disconnect the cable (s) at the transmission end. It’s only a spring clip or maybe a nut. Then you can exercise the shifter to see if it’s still stiff. I would bet the cable is bad where there is a tight bend. Relatively easy and cheap to replace with new cables.

Keysdisease said:

Engine and gear controls are nothing to fix by a half measure.

Click to expand...

Hear, hear!
That admonition should be on a banner over every boater's workbench!