When I first attempted to start my Cummins 6CTAs in November 2022, both engines seemed like they wanted to run, but something was off. One of the problems I discovered immediately was a leak in the fuel return line on the starboard engine’s injection pump. Another problem I noticed while priming the system was that the on-engine mechanical lift pump on the same side was leaking fuel. If the lift pump leaks fuel under pressure when I manually pump it, it may also be pulling air into the fuel supply on the vacuum stroke. That could contribute to the engine not lighting off.
Cracked fuel return line leaks
The return line is attached to the front of the injection pump
Surprise!
I used a cutoff wheel to cut the fuel line behind the bracket that attaches to the front of the pump, which I also thought I’d have to cut to remove the line. But the bracket was broken and the line fell off when I finished cutting through it.
I planned to reuse the flare fitting
Unfortunately, my tube flaring tools don’t fit in the available space
I don’t want to start taking the injection pump apart to make space for my flaring tool. Even if I cut back the tube so it aligns with the flare bar, there’s not enough room for the yoke.
This injection pump wasn’t designed with easy maintenance in mind
The red arrow points to the broken bracket, which is secured to the pump with a bolt. There’s 1/4″ between that bolt and the gear drive housing on the front of the engine; I would have to pull the pump to access it, which would be a massive chore.
You can also see the banjo fitting where the return line attaches to the pump. The nut for that is ~1/8″ from the intake manifold. So, again, there’s no way to remove it without removing the injection pump. I can loosen the banjo nut, though, which allows me to rotate the return line just a bit. And that gave me an idea…
Swagelok fitting to the rescue!
I used a 5/16″ tube to 3/8″ MPT Swagelok adapter to connect the tube to a stainless 3/8″ elbow, and a 3/8″ MPT to 3/8″ flare adapter for the hose connection.
Nice!
I rotated the return line up until the Swagelok fitting came in contact with the injection pump, then used a stainless hose clamp to lock the two together to make a more rigid assembly. Then I attached the hose to complete the repair.
Next, I got a new lift pump. I thought about ordering two pumps just to have a spare, but only got the one. That would turn out to be a mistake, but more on that in a future post. The new pump housing was bare aluminum, so I decided to prime and paint it before installation.
I brushed self-etching primer on the new fuel pump
First coat of brushed on gloss white looks good
I’ve had an unopened gallon of Blue Water Mega Bright White one-part polyurethane paint for longer than I’ve owned this Roamer. It was leftover from the last repaint I did on my 1967 Chris Craft Constellation 52. One-part polyurethanes don’t hold their shine like AwlGrip, but for the engine room this is fine. I thought it might have hardened over time, but after opening the can and thoroughly mixing the paint, it was like new.
Two coats of white was plenty
Easy installation…ready to test fire again
I was preparing to prime the system again when I noticed wet spots on the diaper I placed under the fuel manifold I installed in August 2022. So rather than fill the system with fuel again, I decided to pull the manifold and see if I could stop those leaks.
Next up in our 1969 Chris Craft Roamer 46 Refit: Fixing Fuel Supply Manifold Leaks
1969chriscraftroamer46 
Many decades ago I found that when removing high pressure fuel lines it was easier if both ends were removed together. That was also often the case with any steel line and some copper ones too. Something else I learned was that some copper lines required a special flaring tool. If the wrong tool is used the line will leak.
Thanks Butch!
I’ve definitely noticed it’s best to loosen the opposite end of any tube when I have to remove the other end entirely. Fortunately, with the return line problem I was able to resolve it with a Swagelok; the other end is a banjo fitting. But even then, I loosened the banjo fitting when assembling the Swagelok, and tightened the banjo bolt only after the repair was complete, and the assembly was clamped in place.
Cheers,
Q