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.

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Thanks for your report!  By all means, please post some pictures of where you are in the installation now and continue to post pictures as the installation progresses!  The AeroMomentum engines are yet another great alternative for Zenith builders and detailed reports such as yours will be so helpful when builders are considering engine choices.

I'm sure there will be many builders interested in following your next step in the installation "adventure."  Thanks again for the report - keep'em coming!



Zenith.aero Forum Moderator

Good info. do post pictures also post pictures with cowl on when done.

Hi everyone,

I finally got a chance to take some pics of the mounted engine. The firewall forward fuel system is complete. Started working on the radiator mount today.


More pics


even more pics....



Thanks for taking the time to post this report! I will be receiving my AM15 on Monday so I really appreciate reading your experiences and work-arounds. Please continue to post your experiences, and you've inspired me to do the same for others.



Any thoughts yet to radiator mounting?

Yes. I finished radiator mounting/piping last week, just haven't gotten to posting pictures and insights just yet. I will try to do that tonight.

Do you have any pics of the cowling?

I don't have a pic of my cowling. We haven't started mounting it just yet. But the Aeromomentum facebook page has some pics of the cowling an engine mounts, etc.

Ooooh! Carbon fiber!

The cooling system is complete. Not filled with coolant yet. We plan to use 70% water, 30% ethylene glycol, and add RedLine water wetter per Mark's recommendation.

Mark suggested we mount the radiator with rubber washers, not supplied. If you use rubber washers, the screws that attach the radiator to the aluminum angle will be too short and the supplied small washers wont work either. I found an assortment of M6 stainless screws on Amazon. Also ordered some AN960-916 large area flat washers from spruce. I found some 1/4" thick high temp silicone mat, also on Amazon. I cut washers from the silicone mat with a hole saw.

You can see from the pics where the angle is mounted. Holes drilled very carefully in the gear box mount. The bolts supplied to mount the angle worked fine.

The bottom stiffeners are supplied. I chose to use some of the 3/8" aluminum shim material I had left over to create a mount for the rear part of the stiffeners. See the pics.

You can see from the pictures how some of the of the rubber and steel washers must be cut to clear the stiffeners and hoses.

The two threaded bungs closest to the hose connectors on the radiator are too close. One of them is especially tight, so tight in fact the worm clamp will not fit between the bung and hose, but thankfully there is enough inlet to clamp the hose. However, there is very little of the washers left after they are ground down enough to fit. I hope this can be fixed on future radiator. Maybe there is a reason it has to be so tight, not sure.

As far as the hoses and piping and clamps goes, it is all supplied and just takes some fiddling to figure out what goes where. I pictorial diagram of the routing would be appreciated here to save some time.
I would like some more clearance between the hose and the gnarly starter ring gear.



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