Yanmar 2mg20

[ThunderFog]

I have a Yanmar 2mg20 and when I advance the throttle the spring, internal to the engine housing, are so strong that they pull the lever back to a slower RPM. I have opened and looked at the throttle housing but didn't find any mechinism that would allow me to increase the resistance to the cable to prevent it from returning to lower RPM. Has anyone else had this issue?

[Faster]

Yes, I've seen it before.

Our fix was to cut a piece of 3/8" or so rubber hose, about 1 1/2" long and slit it lengthwise. We tightly hose-clamped one end onto the stationary part of the cable housing, and lightly clamped the other end onto the sliding part, until there was enough friction to prevent the "creep". This can be done at the transmission end or the control end, which ever is easiest to access.

Worked for years.

[trantor12020]

usually near the throttle mechanism, there's a screw you can adjust to increase the throttle cable resistance, thus preventing the throttle from falling back. I faced similar "problem" when I got my boat new. Later I come to understand that it was left resistance free to prevent users running the new engine at high rpm continuously. After engine runs-in, I adjust the friction screw and now throttle works great.

[Goodnewsboy]

I have a Yanmar 2GM and have noticed that the spring resistance to advancing the governor setting is quite high. In order to hold anything more than an idle power setting, some considerable friction force must be introduced in the throttle cable or quadrant or else the spring force will back the power setting down.

Perhaps other engines share this characteristic.

Some boats have a simple "cable squasher" type brake to provide this friction. On Edson pedestal controls of the newer type, there is a friction brake built into the throttle lever mechanism apparently for this purpose.

Unfortunately, I don't have the neat Edson solution, and I recoil at the crudeness of simply crushing a perfectly good control cable, so I will be trying Faster's more elegant fix this spring.

[drynoc]

I had this problem early on when I installed my new engine, but it fixed itself with use.

[doons60]

I have the same issue with my 2GM and can't quite understand the split tube fix.

Any other thoughts out there, it's a bit of a pain to continually adjust the throttle..

Thanks

[Northeaster]

Had the same problem with my 2GM. I read that it is more of a problem when using separate controls for shifting and throttle (on older repowered boats like mine), as opposed to the newer single lever controls.

Someone suggested putting a couple of bulldog clamps on the cable to gently squeeze it - works fine - looks a bit "Mickey-Mouse" in the engine compartment - but does the trick. Dont tighten them too tight, and damage the cable!!

[arf145]

I had this problem, but the fix for my wheel-steering boat was as Trantor stated, and as I read in another posting in this forum: slightly tighten the set screw on the throttle control inside the pedestal. Had to lift out the compass to do this, which was no big deal. For mine, all it took was less than 1/8 of a turn.

Tom

[isimard]

Originally Posted by Faster

Yes, I've seen it before.

Our fix was to cut a piece of 3/8" or so rubber hose, about 1 1/2" long and slit it lengthwise. We tightly hose-clamped one end onto the stationary part of the cable housing, and lightly clamped the other end onto the sliding part, until there was enough friction to prevent the "creep". This can be done at the transmission end or the control end, which ever is easiest to access.

Worked for years.

I realized that solution 3 days ago. I was looking for a solution since I bought my sailboat with a 2004 2GM20 in it. The throttle would slip back to 2800 rpm in less than a minute.

Now I can run at the recommended 3200 rpm and the control is not hard to use, I am very satisfied with that simple and reversible solution. I installed it at the transmission side. Thank you for sharing it

Ivan