Yanmar YB 25 Excavator

[Sprinklerman]

Your machine sounds like one a friend has . Its a John Deere , I cant remember the model . But it was built by yanmar . He bought it new back in 1985 or 86 . He had to rebush his tracks , he had to have pins and bushings made
It has the steel tracks . It is a little beast , he still uses it .

 

[AndyBees]

Well, it has been a bit over three years since I last posted to this Thread.

I've used the little Yanmar Excavator quite often during the past three years.

So, now, I need a starter (engine 3T75H). The brushes are worn out and seems no one has them. There is no info on the starter for reference. Any thoughts?

 

[winston1]

Is yours a 15 tooth? Maybe STARTER ASSEMBLY - GEAR REDUCTION: Yanmar Tractor Parts

 

[bindian]

Well, it has been a bit over three years since I last posted to this Thread.

I've used the little Yanmar Excavator quite often during the past three years.

So, now, I need a starter (engine 3T75H). The brushes are worn out and seems no one has them. There is no info on the starter for reference. Any thoughts?

Any local auto electrical shop should be able to source the parts and rebuild it. I know I can get my old Mitsubishi starter rebuild at one of the shops down here.
hugs, Brandi

 

[O2Bdiggin]

So just reviving an old thread, I recently became the owner of the rare and elusive Yanmar YB25. I’m new and will try and get some pics up soon. So far I’ve done quite a bit to it, new paint, new seat, rebuilt all hydraulic cylinders as well as the rotary unit, replaced the bottom rollers (pretty easy job). Only real issue is smokes like crazy but runs perfect. Easy starts, smooth idle, plenty of power, replaced all injectors, drained fuel system. When I got it the dipstick was frozen so I think the last owner just kept adding oil a little oil here and there, so when I changed it it was way overfilled, about a gallon when it probably only takes a quart or two. I have no blowby at all and just did a block test for gases in the coolant and nothing so don’t think the head gasket is gone, does not overheat and oil not milky. I guess it could be the injector or timing but this thing starts and runs so well it’s hard to suspect the pump. Wondering if anyone has any thoughts?

best,

Rob

 

[winston1]

What color is your smoke? Diesel Smoke tells YOU a Story... - Cost Effective Maintenance.

 

[bmaverick]

So just reviving an old thread, I recently became the owner of the rare and elusive Yanmar YB25. I’m new and will try and get some pics up soon. So far I’ve done quite a bit to it, new paint, new seat, rebuilt all hydraulic cylinders as well as the rotary unit, replaced the bottom rollers (pretty easy job). Only real issue is smokes like crazy but runs perfect. Easy starts, smooth idle, plenty of power, replaced all injectors, drained fuel system. When I got it the dipstick was frozen so I think the last owner just kept adding oil a little oil here and there, so when I changed it it was way overfilled, about a gallon when it probably only takes a quart or two. I have no blowby at all and just did a block test for gases in the coolant and nothing so don’t think the head gasket is gone, does not overheat and oil not milky. I guess it could be the injector or timing but this thing starts and runs so well it’s hard to suspect the pump. Wondering if anyone has any thoughts?

best,

Rob

Rob,

Seeing the above YB25 has a 3T75H engine, and a few of the YM tractors do, 10W30 would be the oil grade most popular for the machine. The Yanmar engines are engineered to JIS standards, thus, the oils are not the Big American Iron use of 15W40.

 

[O2Bdiggin]

Ok, thanks for that info. I am running shell rotella 15w40 and will try 10w30 and report back

 

[O2Bdiggin]

What color is your smoke? Diesel Smoke tells YOU a Story... - Cost Effective Maintenance.

It’s definitely a tint of blue but I don’t seem to burn any oil.

 

[O2Bdiggin]

Changed the oil today and added 10w30 full synthetic, I added 3.5 quarts which measured about halfway on dipstick. Definitely a lot less smoke coming out of exhaust, I’ll see if it completely goes away in a couple hours or running, thanks bmaverick.

when I was pulling drain plug I saw some fuel dripping from what looks like a fuel pump on rear part of engine. Didn’t know it was there. Looks like it could be a crankshaft driven pump. Is that right that these engines have manual fuel pumps, most older diesel equipment I’ve owned has been gravity fed systems.
thanks

 

[bmaverick]

I only have a 3TN75 parts manual at this time. It's the next generation of the 3T75 engine. I would expect much of it to be either the same or very similar.

The 3T75 engine was used in many of the machine models you have and the F16/FX16 & F17/FX17, YM1601, YM1602, YM1610 tractors.

Now, the YM1810 is a direct match up to your machine of the 3T75H. This parts manual should be down right identical except for how the engine is mounted in the machine. See attached.

Compliments of the Yanmar Tractor Owners Group on GroupsIO (was Yahoo) link in my signaure

 

[O2Bdiggin]

with no resolution on the smoke and the suspicion I was burning coolant as my smoke problem I decided to pull the head and replace the head gasket. Not a bad job and followed the procedure outlined by Hoye. In short it did not fix the smoke Issue. I pulled the thermostat housing and there Was only remnants of what used to be a thermostat (a spring and some metal) so clearly not ever getting up to operating temp. Smoke improved but still pretty bad. At this point I started to suspect the injector pump. I changed the fuel filter and noticed quite a bit of rust dust in it. I pulled all the injector lines and when cranking the engine one plunger was sending gobs more fuel than the other two. Reading how sensitive these injectors can be to contamination on Hoye website I opted to replace the whole injector pump And fully clean and decontaminate the whole system. I used a sand blaster pressure washer kit to blast the inside of the fuel tank, then navel jelly and a chain, then pressure washed again. I let the tank bake in full summer sun for three days and reassembled the whole fuel system with all new lines and filters. I added an additional inline filter from the tank to injector pump and placed rare earth magnets everywhere on the fuel tank and taped to inline filter to catch any remaining rust dust. Took several attempts to shim the injector pump just right for the timing but three seemed to be the magic number and now no more smoke. There’s the usual puff at startup but it’s finally running clear like it should! Finally!!

 

[ponytug]

Congratulations!