Injection servo mount fix

This was another of my FWF tasks that I’ve been putting off for a while. I discovered some time ago that as provided, the FM150 fuel injection servo interfered with the bottom cowl. I also determined that if I removed the 1/2” spacer between the sump and the servo, the clearance issue went away. Some research indicated that the only reason that spacer is there is because Superior provides really long studs with their cold air sump. That is, it’s just there to accommodate the mount hardware.

Well, as part of a Spruce order I put together last week, I figured out what studs I needed here and got those added to the order. That just left the fun of removing the old ones and installing the new ones. Removing these was a lot more fun than the alternator ones from a few days ago – these were really tight, to the point that my first attempt to remove one using two nuts and some heat failed miserably

I was on the brink of ordering a special stud removal tool, but I decided to give it one more try, this time being more generous with the heat. Turns out that about a 30-second blast with a Mapp gas torch puts enough heat in to break the stud loose, so I was back in business. Most of the fun came from figuring out how to orient the torch to heat the stud without destroying anything else in the area, like the rubber intake boots visible in this photo of the stud-less sump:

This led to a surprisingly long and tortuous discovery session. You see, at a glance, it looked like the studs I ordered were too short to fully engage the sump while also providing enough length for the servo and the mount nuts. I actually came pretty close to ordering another set of studs that were 1/4” longer…oh, and those studs were $18 each.

What made this fun was that I didn’t want to just install a new stud without knowing it was right – so I ended up measuring, re-measuring, reading up on proper thread engagement, and so on. Eventually I decided that these studs would work, to the point that I was confident installing one. But it was also critical that I thread the studs in to a very specific depth, so I ended up using a washer stack on each stud to give me a nice precise stopping point during installation.

After all that worrying, the first stud I installed gave me the chance to verify I had good engagement with the servo, and then the other three went in in about ten minutes. Finally, I got the servo back in place, torqued all the mount nuts, and reinstalled the fuel lines. After being temporarily mounted with a lot of stacked washers for a while, this servo is finally back in place for real:

I guess I can’t really put off cowl trimming any more now. That’s going to be a lot of fun, seeing as how it looks like we’re going to have near-triple-digit high temperatures for the foreseeable future. Sweat and fiberglass dust are not a very enjoyable combination…

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