Hi everyone,

We decided on using the Aeromomentum AM15  117hp engine during Sun n Fun last year. Our engine was finished and ready to ship in the normal lead time, but there were major delays in getting the cowling, We decided to wait on the cowling and have everything shipped in one crate.

We mounted our engine about a week ago and reached a milestone in our build.

I say we, because my good friend Larry and I are in this as build partners. We purchased a scratch built 750 Cruzer about a year and half ago and have been planning and finishing the build. It took about 6 months to actually decide on which engine to use. Together we decided the Aeromomentum was the best value of the lot, and really liked the engineering of the engine. Mark also was a big factor in the decision. He has always answered every question we have had promptly and intelligently.

But the real reason for my post is to document our experiences with the engine so far, purely to help other builders that are about to cover the same ground or would like to consider using Aeromomentum.

The first problem we encountered was the clearance of the engine mount to the puck nosegear system. After conferring with Mark, we created 3/8 inch thick 6061 aluminum shims, which we installed between the mounting flats and the airframe. This gave us the clearance we needed to the pucks. Mark says the next batch of mounts will be 12mm forward to clear the pucks.

When mounting the engine, we soon discovered that the bolts supplied with the engine were too long. Even with 4 washers behind the castle nuts, we could not get the bolts to work.

So, we ordered AN6-44 from aircraftspruce, which proved to be just right.

We used an engine lift and numerous ratchet straps to lift the engine off the crate and get the engine horizontal, we could then fine tune the angle to get the engine to line up with the mounts. This worked great. All spelled out in the Aeromomentum manual.


There are dual fuel pumps supplied in the firewall forward kit and 5/16 Helix racing hose for the pressure side of the pumps and 1/4" Helix for the return from the fuel rail and fire sleeve to cover these lines.

The hose needed to supply the pumps is not included, not sure why? It was labeled as 3/8 inch in the manual, however the input to the pumps is 1/2". A quick response from Mark, led to the discovery that 3/8 Gates hose will fit on the fuel pump inlets. We chose a length of Gates barrier 3/8" hose, high quality. It WILL fit, but you better eat your Wheaties and use some silicone grease! No way those connections will ever leak. We used Oetiker clamps on all fuel fittings.


This is next adventure on the list, will keep you posted.

Pics can be supplied if anyone is interested.

Views: 7202

Reply to This

Replies to This Discussion

More cooling system pics


Even more cooling system pics


Looks great!  Have you received your cowl yet?

Yes, received cowl December of 2019, actually waited about 9 months to get engine AND cowling shipped together. It was frustrating, I must say. I do wish the cheeks had been preinstalled, not really looking forward to mounting the cowl and cheeks, sounds like it will be an adventure. 

Hi Tim I have mounted mine its not that bad I can send you some photos.

As an aside I received my engine and cowl around the same time BUT have found my spinner and mounting plate do not match one says 5 and the other 4 so Mark has emailed some builders that were sent spinners at the same time to see who else has a miss match. Would you mind checking yours for me? 

Yes, I had to send my spinner back to Mark, as the screw holes did not match the backing plate. Lili shipped me a new spinner of a different type, from a different vendor. I had to create the spinner to backing plate holes myself, first using clecos, then nutplates and screws. Very proud of how it turned out. Makes me think about using the same nutplate/screws to mount the cowl also, versus 1/4 turn camlocs.

I would love to see the pics of your cowl, as I started trimming the bottom cowl yesterday. The location of the cheeks is the main thing that is unknown. Even with the CAD drawings , its still not all that clear.


Looking good, how long ago did you send it back? Ill have to follow them up, the freight from here in NZ to the states is horrendous.

Any way attached are photos of the cowl, I had to move the scoop at the bottom forward as the radiator was going to be too much of a tight fit.

The Cheeks were not so bad, just had to cut it and get it done, then faired it in with resin.


Thanks for the photos, very helpful.  I sent the mis-matched spinner back to Aeromomentum October 20th. Lili sent postage label for the return of the bad spinner with the new spinner, per my request. 

Tim looking good. Just wondering if you ever got around to weights of the aircraft yet. Im getting closer to starting to build. Your building just what I want. 

No, wings aren't mounted yet, so we haven't gotten to a final weight yet. I will post it when we do.


Great info in your posts.   How is it going, are things progressing well with the engine?


New from Zenith:

Zenith Planes For Sale 

Classified listing for buying or selling your Zenith building or flying related stuff...

Custom Instrument Panels
for your Zenith

Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, Dynon and Garmin avionics, and more.

Zenith Homecoming Tee:

Zenair Floats

Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz

Builder & Pilot Supplies:

Aircraft Insurance:


West Coast USA:

Pro Builder Assistance:


Transition training:

Lavion Aero

K&S Aviation Services

Aircraft Spruce & Specialty for all your building and pilot supplies!

How to videos from HomebuiltHELP.com

Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit HomebuiltHelp.com for the latest DVD titles.

© 2024   Created by Zenith.Aero.   Powered by

Badges  |  Report an Issue  |  Terms of Service