Fuel line Leak Discovered

[Christian Williams]

The oil-absorbing pad under my 5432 diesel turned red. Oh dear. Red is diesel fuel.

I figured my aft-most injector body had come loose, since fuel seemed to collect there. I brought the special tools required to tighten an injector.

But another test run narrowed the issue down. The leak wasn't the injector at all, but instead the small hose of the fuel return between cylinder 3 and 4. With the engine running it sent a fine spray onto the injector. That was obvious on a paper towel placed there.

Easy fix, if I can find the odd-sized fuel hose. I couldn't, when I took the Kubota size around to boatyards and diesel shops a few years ago, when servicing the injectors.

I'm guessing 1/4" ID, which might be too large. But the Internet source will have it here in one day, and returnable for free.

 

[G Kiba]

The hose diameter is likely metric. Not that uncommon any more.

 

[Christian Williams]

Hard to find. My semi-local Kubota dealer identified the part--#1 on this view.

But Kubota doesn't reveal the hose diameter to the parts counterman. Each piece comes cut, for about $1.50 each. Special order.

I'll try to get the 1/4" to work first.

The key to the part number in my case (Universal 5432) is V1301 (engine block) and tractor model (L345)

 

[Bolo]

The oil-absorbing pad under my 5432 diesel turned red. Oh dear. Red is diesel fuel.

I figured my aft-most injector body had come loose, since fuel seemed to collect there. I brought the special tools required to tighten an injector.

But another test run narrowed the issue down. The leak wasn't the injector at all, but instead the small hose of the fuel return between cylinder 3 and 4. With the engine running it sent a fine spray onto the injector. That was obvious on a paper towel placed there.

Easy fix, if I can find the odd-sized fuel hose. I couldn't, when I took the Kubota size around to boatyards and diesel shops a few years ago, when servicing the injectors.

I'm guessing 1/4" ID, which might be too large. But the Internet source will have it here in one day, and returnable for free.

View attachment 44078

Didn't know that there were special tools required to tighten/remove an injector. What are they and what do they look like? Anything special order for $1.50 is a bargain unless the shipping is $25 or something higher. I've seen that scam before.

 

[Christian Williams]

Just bigger socket and spanner than I usually keep on board.

E381 - Fuel Injectors Service

Small diesels are renowned for their simplicity. They have no ignition system and in a pinch they'll run on cooking oil. Diesel fuel doesn't aspire to be napalm, and unlike gasoline feels almost natural on the skin. Diesels work forever with...

ericsonyachts.org

 

[Teranodon]

After an adventure with one of the injectors a couple of years ago, I carry a 17mm dedicated wrench in the engine compartment.

 

[Bolo]

Just bigger socket and spanner than I usually keep on board.

E381 - Fuel Injectors Service

Small diesels are renowned for their simplicity. They have no ignition system and in a pinch they'll run on cooking oil. Diesel fuel doesn't aspire to be napalm, and unlike gasoline feels almost natural on the skin. Diesels work forever with...

ericsonyachts.org

I thought that there was some "secret" tool that I didn't know about but I'm fairly sure that I keep that size spanner and large sockets on board. My wife says that I probably have too many tools on board but after seeing you post...How many tools are too many?

 

[Teranodon]

I thought that there was some "secret" tool that I didn't know about but I'm fairly sure that I keep that size spanner and large sockets on board. My wife says that I probably have too many tools on board but after seeing you post...How many tools are too many?

It is a special tool. The socket is split to allow it to go over the fuel line. Just google "injector wrench".

Too many tools? Huh?

 

[Bolo]

It is a special tool. The socket is split to allow it to go over the fuel line. Just google "injector wrench".

Too many tools? Huh?

I know...too many tools. What a silly girl my wife is sometimes. Too many shoes?! I'll have to check the injector wrench out and get one because soon or later......

 

[Alan Gomes]

The hose diameter is likely metric. Not that uncommon any more.

How about McMaster-Carr?

 

[Tin Kicker]

Seems to me that Tygon 6mm yellow fuel hose fit.

As for tools, using two open end wrenches works. The socket would be required if following the manual and trying to get the perfect torque, but then these were meant to be tractor engines. Get the torque about right on the injector with the 17mm, then hold it while tightening the nut for the line with the smaller open end (iirc 15mm).

 

[Christian Williams]

On the 5432 a deep socket doesn't fit over one or more injector bodies, and must be modified. Wrenches alone won't do it.

 

[Tin Kicker]

The wrenches were not fully seated and it took a little finagling to get in there, but then the injectors are not highly torqued.
Obviously, the rubber line comes off before the wrench can go on the injector itself.

[Upside down to how installed]

 

[Kenneth K]

The leak wasn't the injector at all, but instead the small hose of the fuel return between cylinder 3 and 4.

If you haven't replaced the long fuel return line to the tank, that's probably worth doing as well. Seems I've read a couple of posts where owners had leaks there, too.

 

[Mr. Scarlett]

I found some of the same hose at an outboard shop.

 

[Christian Williams]

Here's the break. Could be a nick prior to install, but who knows?


I now recall I installed these return hoses myself several years ago , using stock 1/4 inch fuel line. This week I bought new 1/4", with as it happens a thicker wall thickness.

The nipple is 5 mm. The 1/4"ID hoses work, but don't compress well and the seal, even with hose clamps, is not satisfying. It works temporarily, and would probably heat-conform quickly.

...

But I'm ordering the proper Kubota hoses. As I recall they are a smooth material, stiff, not at all like this rubber, more like the oil vapor line in foreground of the photo above.

 

[nquigley]

It is a special tool. The socket is split to allow it to go over the fuel line. Just google "injector wrench".

Too many tools? Huh?

They're fun-looking tools. Who wouldn't want a set? ... and less than ~$40 too!

Amazon.com : injector wrench

www.amazon.com

 

[RCsailfast]

Ordered the Kubota hose when I ordered injectors and it was the wrong size. Too big. Ordered the hose from Toad marine and got the wrong size hose.
Ended up reusing the painted gold hoses and thankfully no leaks. I know it’s a matter of time before they fail. Hopefully there is a known correct replacement found.

 

[Puget sailor]

Too bad that they are not more like Yanmar’s solution, which is rigid pipes instead of hoses. I guess in theory there is not so much pressure on the return side. “In theory”

 

[phildogginit]

On my universal m25-xp a mechanic replaced the original return line pieces with 3/16" fuel line from Greenline product G611-019. They are long enough that they did not need clamps and do not leak. The pressure on the return side is not high, and open in the fuel tank.