Yanmar YSB-12 Start Problems

[solesurchin]

Hi All,

I sail a Miura, a 31' South African built boat form 1975. My dream boat, solid and capable running a Yanmar YSB-12 which is normally reliable.

Lately the Yanmar has been having trouble starting. All the normal things [fuel, air, compression] are healthy and once she runs there are no problems. But starting, either cold or hot, is an issue.

Through lots of poking about and jiggling every which thing, I've discovered the culprit. [see attached image].

I do not know it's function. It's linked to the throttle somehow and if it is firmly pulled forward while trying to start the motor fires up and runs perfectly.

Does anyone know what this "thing" is and if it is adjustable or replaceable? and why would it influence start-up behaviour?

 

[kappykaplan]

When the engine starts, is it at a fast idle when you pull the "thing" forward?

 

[Johnb]

Yanmar YSM12-R Marine Diesel Engine Service Repair Manual

This is the Highly Detailed factory service repair manual for theYANMAR YSM12-R MARINE DIESEL ENGINE, this Service Manual has detailed illustrations as well a…

www.slideshare.net

This might help

 

[solesurchin]

When the engine starts, is it at a fast idle when you pull the "thing" forward?

I haven't tried fiddling once it starts. Perhaps that's worth investigating...
One thing I have noticed though, I cannot get the motor to start unless I have full throttle set.

 

[solesurchin]

Yanmar YSM12-R Marine Diesel Engine Service Repair Manual

This is the Highly Detailed factory service repair manual for theYANMAR YSM12-R MARINE DIESEL ENGINE, this Service Manual has detailed illustrations as well a…

www.slideshare.net

This might help

Thanks. I'll take a look....
Ok. Found a YSB8/YSB12 manual here. Looks like the lever is the "fuel-injection regulator" and there is a description/procedure for adjustment.
I'll try adjusting as per instructions and report back.

 

[kappykaplan]

One thing I have noticed though, I cannot get the motor to start unless I have full throttle set.

Anecdotally, my Universal wants 1500 RPM to start. It won't start with the throttle at idle.

 

[solesurchin]

It's been a long while but I thought to provide some feedback on the starting issue
It was indeed the governor that required adjusting. There is a detailed description on the adjustment procedure here Yanmar YSB 12 Hard to Start
Once adjusted the little Tanmar does not even require decompression any more and fires up within 2-3 turns of the starter.