Injector pump leak - tightening?

[soopad00pa]

See pic.

I have a leak at the nozzle marked A on my pump, at the base nut. None of my wrenches fit in between everything, so I think I need to take more stuff apart, but I'm not experienced with engine stuff so I'm gonna lay out what makes sense and hopefully you guys can make sure I'm not gonna burn down my boat.

Unscrew at C and B so I can slide a wrench along the line/pipe to get to the top nut at A. Removing the top nut at A will let me fit a socket on the base nut at A.

Tighten and reinstall the line. Bleed fuel. Done.

Make sense? If so, anything I need to be aware of during dis/reassembly?

Much appreciated...

[Wotname]

Usually there is a seal below the base nut A, often a O'ring. Remembering the pressure in the injector line is around 2,500psi, a simple re-torquing the base nut is unlikely to stop the leak.

First step is to get the service manual for the engine / injector pump and understand what is below the base nut and why.

If you post the engine model, others here may know what is the best approach.

[Ironshorts]

You need to know about this:

https://www.constructionequipment.co...ly-devastating

Never check for leaks with your fingers use a long bit cardboard instead.

[soopad00pa]

It's a 1983 Universal M25. I've got the manual. I should be able to track down new O rings.

Is it under pressure when the engine isn't running?

Also, it's a visible leak - when running, there's bubbling fuel at the base of A. Not much, but noticeable.

[Allied39]

I swear I adore this website, entertainment like this just can't be bought.
Oh,,,,,wear eye protection.....

[jamhass]

Try a "flare nut wrench." Not expensive and they fit MUCH better than regular wrenches, and need less circumferential clearance, so can fit where regular wrenches don't.

[Wotname]

Originally Posted by soopad00pa

It's a 1983 Universal M25. I've got the manual. I should be able to track down new O rings.

Is it under pressure when the engine isn't running?

Also, it's a visible leak - when running, there's bubbling fuel at the base of A. Not much, but noticeable.

Yes it is under pressure when not running unless it is leaking .

There is a delivery valve (AKA check valve or no return valve) at each end of the steel injector line (i.e. one in the injector and one in the injector pump). These maintain the pressure in the injector line when engine isn't running but there is so little fuel in the injector line you will not notice the release of the pressure when you crack the nut. The ID of the injector line is about 2mm (3/32").

If you decide to replace the seals yourself, do ensure everything is scrupulously clean as this is downstream of your fuel filter.

[Nekton73]

There are slotted box wrenches made for just this reason, or you could just buy one and cut the required size slot yourself. I've made several for different situations and never regretted the few dollars spent on an extra wrench vs how easy it made the job.



However, the comment regarding o-ring failure is valid and a likely possible reason for your leak. Tightening may solve the problem temporarily, but maybe not, or the leak may come back soon if the ring has dried out. If the rings are original it would be a worthwhile r&r to do on the engine and then you won't have to worry about it again for a long time.



Don't worry, removing injector lines, picking out o-rings, installing new ones, tightening, bleeding and starting up again is not as hard as it may seem. Not much can go wrong unless you over tighten or strip something, which is unlikely if you are careful. Clean everything thoroughly so you don't get any paint flakes or dirt in the seats or ports when you open things up.



The slotted wrench I mentioned earlier will probably be of help no matter what and will make a good addition to your boat tool kit in case you have to work on the lines again.