Minkuni carbs

[kip51035]

Now that a lot of the old engines with "A" boxes are turning into small boat anchors, these boxes are starting to hit the market. People are going to have them mated to a snow machine engine. I have done it. The results are that I seized up the engine and just about every one else that tried this did. I suspect that the carbs do not give a proper spray at full power.

Kip

[Trev Page]

Just another reason to stick with Rotax engines provisioned with gearboxes in mind and Bing carbs I guess.

Mikuni from what I remember will not sell a carb for aircraft use hence the usage of Bings.

I had a bad experience with a brand-new Hirth 5 years ago but my experiences with Rotax have been very good. My new plane has a 912 in it and I had a few issues, Rotec was excellent with their support and helped me sort things out. More than I can say about the folks representing Hirth in the US.

[Matthew Roung]

Wouldn't be the fault of the carb. Probably just not jetted correctly for the application. When I installed a snomo engine on my plane, I went to much richer main jets. A bing is a crude carb when compared to the Mikuni, if I had one of the 582/503/447 etc. series engines I would toss the Bings and install Mikuni's. I think for the 912's, the Bings are altitude compensating? I don't think there is a comparable carb from Mikuni.
-Matt

[Trev Page]

Yeah, the carbs on the 912 are altitude compensating. Not that I've ever tried that function, I haven't been above 5000 feet.... ;)

[CrashVenturie]

Got a 503 coupled to a b box and 2 mikuni carb, run like a charm all temp are in spec, unfortunately i don't know the jet setting on them next inspection i'll take notice.

[Aeroquest]

Just looking around this site and came across this bit of rubbish! You guys have to get off the brainwashing bit with the so-called Rotax aircraft engine stuff. 99% of the time a 2 stroke engine packs it in, is because of pilot error...that's all 2 strokes (or any engine for that matter). Do you guys think that Rotax makes a different engine (say the 503 for example) for aircraft compared to the sled version?

As for Mikuni vs Bing...Mikuni would not sign a liability agreement for use in aircraft. Bing be a smaller more needy company did sign. No witch craft here! Bing is a crapp crab anyway...Mikuni has way more variants (in terms of jetting and slides) than Bing.

[Matthew Roung]

No.....nope, no brainwashing here. What gave you that idea? Neither do I believe that the 503 in your sled is the same as the 503 in your plane. Not 'better', or more 'reliable' mind you, but not the same. Aside from different carbs and electrics, there are a few internal differences. The a/c version, for example, has cageless needle bearings in the small end, while the snomo versions are caged. Prob most other parts are the same. I would say it's a bit of a myth that the a/c versions are built with stronger parts (crank, rods, pistons etc.). If anything, I would suggest the snomo's get the better parts (like carbs and electronics). Ski-doo prob sells 1000 snomobiles for every Rotax engine sold for aircraft. Why would they put 'inferior' parts in the snomo engines, by far their biggest market (with competition!)?
-Matt

[Aeroquest]

Maybe not you Matt, but there are lots of people that think or are lead to believe that they are safer flying a UL Rotax then any other 2 stroke. This is poor instruction when you put more faith in your machine than your own pilot skills.

We have many "alternate" 2 stroke engines flying around here. Have had only the regular maintence and common troubles. Don't install Rotax anylonger as they have called us many times telling us to stop using sled engines in aircraft applications. Suzuki does not seem to mind though? Nice engine...and up to date, unlike Rotax.

[Matthew Roung]

Speaking of up-to-date engines, I wonder if anyone has adapted one of those PWC 4-strokes for aircraft use yet. Sea-doo, Yamaha, Kawasaki, Honda all have mostly motorcycle based engines in their watercraft, one could buy the whole boat for 1/2 what a Rotax 912 costs. All these engines are 150hp or more, and have been well tested and proven. If I ever replace the Subaru in my Buzzard, it will be with one of these. Actually, I have been keeping my eye open for one of these engines, havn't found one yet!
-Matt

[Aeroquest]

Have not seen or worked on one of the 4 stroke jet drive engines...I know the 2 strokes use the jet pump to pump the cooling water around the jacket. The 4 strokes should be similar and if this is the case impractical for use anywhere except in a lake. I know one guy got a big 2 stroke PWC and started to install it in a trike, untill he saw it did not have a water pump like we know. No casting even there...had to scrap the idea.

BW

[Matthew Roung]

Not sure myself as to what kind of pump they use. Even if that is the case though, that the pump is integeral to the jet pump, it still would not be a big problem. Adapt an automotive-style, belt-driven water pump to the engine.
-Matt