Looking for input from 701/750 owners with Viking engines. positives/negatives, attiboys and aw shits.  Specifically, total installed weight, cooling, gph.  Running auto gas is very important to me, I look forward to your thoughts'


Thanks, cheers,,,,,,,,,,,,  Lynn in Washington state

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I made this page http://www.stol750project.info/engine-selection/ a long while ago, it was probably inaccurate back then so take with a pinch of salt. But those were the major options I was looking at and it helped me to write it all down.

For me, unless after 200 hrs they start falling out of the sky, I'm going with the Viking.

Thanks for the reply Paul.  I am unable to open your selection attachment??  The Viking looks like a great choice, just wondering if it might be a little too much for the 701.  Your project looks great,  where are you located?


Cheers,,,,,,,,,  Lynn

Hi Lynn, Thanks for the kind words. I'm in the south of south California, just a stone's throw from the Mexican border.

I have a Viking engine I recently mounted on my plane. I dont have operating experience with it yet, so I can't offer up anything on that end. But it's a very fine piece of machinery thus far,
A-1 quality in design and workmanship. I'm very happy to have it.

It was my first pick until I got too good of deal on a "real" airplane engine.  I've heard of some issues, but so far the reports are pretty positive.  There's a guy named Jeff that has a great blog on his 750 build with a Viking.  Look here


He's good at answering questions about his build too!  If my engine tanks or turns into a money pit, I'll most likely go Viking!

I don't know about the Viking/Honda, but the Subaru conversion has been around for 20 yrs. And I still hear reports of troublesome installations - my neighbor/A&P gave up on his recently after many attempts and went to a   Lycoming. Hopefully, the Viking will turn out better, but early-adopters should probably proceed mainly for the love of experimentation considering the history of auto conversions.

Yes John and dont forget that the same guy that was doing the Subaru engines(and no longer supports them) is now selling you the Viking engines.

Hope Jan does a better job in the future with Viking.

Only time will tell.

I have just under 100 hrs. on mine so far.

VERY happy with it !

With a 701, slats removed I get 5.5 gph at 5000 rpm. 85 mph. And yes, it will do 100 mph but with one hell of a fuel burn.

I'm thinking of a 650 build with another Viking engine & Dynon. That should say something about how I feel about the engine.


Dan Stanton

The only thing that worries me about the Viking is the PSRU.  The engine itself seems to be bullet proof and is well proven.  Since it was originally designed for an outboard motor use, unlike the Subaru (similar high, constant RPM use as a aircraft engine) it should work great as an airplane conversion. 

In fact there are pictures comparing the Honda and a Rotax  crankshaft and the Honda crank makes the Rotax look like it came from a Tonka toy, so I don't doubt the engine is up to the task. Any issues IMHO will be from the PSRU.  Until they start getting at least 1000 hours or so on them (I don't think any have but Egg's original one was sold with over 600 with no problems) I'd be a tad paranoid about it.  I would like to see a few engines make it to over a thousand hours or more and torn down for detailed inspections.

Rotax makes an awesome engine, but there is no way they will convince me that it cost the price of a brand new truck for a four cylinder engine!  That would go for Lycoming and Continentals as well!  Sure there is a lot of R&D and development costs but we're still getting raped just because the companies have no competition and can get away with it.  If we don't start seeing products like the Viking out there, recreational flying will become a truly unaffordable hobby, not that it's cheap right now. ;)

Many times something new or unusual creates suspicion or doubt. I remember when the Rotax 4 strokes came out. I'm not exactly crazy about some auto conversions but I consider the Viking application to be as real of an airplane engine as any , even better than some. I can also find fault with any engine such as Jabiru (cooling and head warping), Rotax (crank cracking), and just old heavy carbureted air cooled technology. The ntsb archives have many fatalities associated with the tried and true o-200 malfunctioning. I appreciate ingenuity and the very nature of "experimental" aviation. For my experimental aircraft, the Viking inline 4, injected, fully liquid cooled, $12,500 engine designed for racing, fits the technology,engineering, and economy curve precisely. Happy hunting...

Lynn - When (2003) I built my 701 180 lbs max firewall forward was the recommendation. What is it now?

Hey Chris, 185 is the new # and 100 hp.  The Viking says it's 178 & 110, guess I better talk with both Zenith & viking.   Cheers,,Lynn


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