Yanmar Problems

[donradcliffe]

Reporting back--Changed out the primary and secondary filters and problem is solved. Can easily hit 3800 rpm in gear at the dock. Thanks so much for all your advice.

After I changed filters, I took a closer look at the vacuum guage on the primary. It reads about 3 psi with a new filter. Closing the valve to the fuel tank creates a rapid vacuum increase, so all seems well. Just wondering what is normal for that gauge.

I did clean some gunk out of the primary filter separation bowl, and the old primary filter element felt heavy like it had a load of sediment in it. Could be that the fuel I got from 'Diesel Steve on the dock in the Ala Wai might not have been the cleanest stuff around....

It was a good day--I think I also fixed the three speed shifter in the coffee grinder--next project is the head.

[DavefromNZ]

4JH5E Support bracket for throttle linkage and dipstick cracked. Only 5 years old. No reason.

[delmarrey]

I'd say too much idleing. Also need better support for vibrating parts.

[DavefromNZ]

Nope definitely not much idling. In fact I am rather poor at warm up and cool down. I suspect just a poorly made part.

[a64pilot]

I doubt that it’s poorly made, it looks exactly like high cycle fatigue.
Almost certainly it was vibrating, it’s resonance frequency was at some operating RPM. You can change that frequency many ways, but usually it’s changed by stiffening the part by adding a brace to it, welding a gusset to the corner for example.
If you replace the part, its very likely to fail again, but a proper repair should outlast a new part.

[delmarrey]

Originally Posted by a64pilot

I doubt that it’s poorly made, it looks exactly like high cycle fatigue.
Almost certainly it was vibrating, it’s resonance frequency was at some operating RPM. You can change that frequency many ways, but usually it’s changed by stiffening the part by adding a brace to it, welding a gusset to the corner for example.
If you replace the part, its very likely to fail again, but a proper repair should outlast a new part.

Agreed! L brackets have many failures on vibrating machinery, motors or otherwise. That's the reason for corner gussets especially on motor mounts. If you can flex the metal by hand, chances are it'll crack, on a pleasure size boat.

As well, when ever metal is bent it causes minor fractures and work hardening. IAWs the damage is done before it's even installed. And as close as the holes are to the corners of the bracket, I'd guess the corners would break off next.

I'd suggest using a piece of extruded angle iron with corner gussets. The other alternative is increasing the thickness of the metal, maybe double thickness.

The buttons under the bolts are not very supportive.