Good day,
My buddy purchased a few things from someone cleaning house, including a brand new 2stroke Mutnug Millenium .65 ball bearing, ringed powerhouse. It is a SWEET engine, and a screamer. He put it in an LT 40 and it will almost hover. NO ONE has seemed to have heard of this engine. Could this be a private label or something. It really is a fine engine.
Has anyone heard of this?

Thanks,
Spanky

Are you sure it's not a Mutunic?

It is either MUTUNUC or MUTUNIC (as Hobbsy said..) wayyy to cold to go out to the shed and look! I am in San Diego you know-

It is made in Taiwan- Dual BB and a sweet runner!

I have only had mine on the stand (No plane for it at this moment..) and it hand starts first flip, has great throttle response and the power seems strong!

I posted a couple of questions on here a couple weeks ago- It was like a ghost-town!

Mine is broken in already I got it in a trade deal and it runs much better than I was suspecting...

Keep in touch!

I still have no idea what % fuel or prop sizes

Now wait a minute, San Diego. Like, how cold can it get? Here the sun is shining and 8 below zero! Its sort of like a cruel joke.

Anyway, do you know about parts for the engine? Any suggestions? Can you still buy these engines?
Thanks for the input.

Spanky

Some years ago, I purchased a Mutunuc 65 ABC 2-stroke engine from Sussex Model Centre. SMC were the sole importers of these Taiwanese engines, which were apparently good quality copies of one of the earlier OS engines (certainly most dimensions are identical to the OS 60 FSR).

The engine started well “straight out of the box”, throttled well, ran reliably and produced an impressive amount of power. I fitted it to my Avicraft Panic biplane, and have thoroughly enjoyed flying it. The engine produces slightly more thrust than the weight of the Panic, so vertical performance in particular is very good.

As the engine has continued to run in (a process that happens over quite a long time with ABC engines) it has been necessary gradually to lean the mixture at the bottom end in order to get both a reliable idle and a clean pickup. A few weeks back, however, I reached the point where the slow-running mixture could not be made any leaner, and from that point on the engine became less reliable and more difficult to tune, ruining two or three flying sessions as a result.

The problem lies within the Mutunuc carburettor. It is a simple twin-needle type, with an open-ended spraybar. The slow-running needle fits into the open end of the spraybar, closing off the opening progressively as the carburettor barrel is rotated closed.

Unfortunately, the slow-running needle has a “shoulder” on it, and a point is reached where this shoulder contacts the end of the spraybar at very low throttle settings, preventing a suitably lean mixture from being set at slightly higher throttle settings.

Graham Bankes also has a Mutunuc 65, and he also encountered this problem with his engine. He informed me that he had substituted a spare Irvine 60-sized carburettor (reclaimed from a crash damaged engine), and the Mutunuc was restored to its previous impeccable manners.

Not having a spare 60-size carburettor to hand, I set about seeking a suitable replacement. Mutunuc spares are no longer available, even if I had wished to obtain another carburettor of the same flawed design. An Irvine perhaps? Dave Richards had just purchased one so he knew how much they cost..... £30 all bar pennies! Surely there must be a cheaper alternative.


Turning to the Just Engines catalogue, I found that they stock three carburettors of suitable dimensions (15mm fitting, with an 8mm or better venturi). The most suitable one of these appeared to be the JEN ‘PRO’ - a copy of the OS Type 6x carburettor at only £20 (the full OS version is just under £50).

A quick email to Paul Landels at Just Engines confirmed that this would be the best choice for the Mutunuc, and an order was duly placed.

When the carbie was fitted to the Mutunuc the engine was transformed. Idling is now steady and reliable, pickup instantaneous, and the top-end power is slightly more than before thanks to the slightly larger 9.5mm venturi.

All in all, the carburettor is very nicely constructed, and represents excellent value for money. It would be an excellent, low-cost replacement for any medium to high power engine, particularly, thanks to that large venturi, if a fuel pump or tuned pipe is being used.

The 15mm fitting suits Irvine 60s, most Chinese 61-1.08s, Super Tigre 60/75/90s and Mutunuc 60/65s amongst others. So if your 60 to 90 size engine suffers crash damage to the carburettor (or if you just need a replacement carburettor) and it is a 15mm fitting, then the JEN ‘PRO’ is well worth considering as a quality, low-cost option.

Thanks Razor.
I copied what you put and sent it to my cousin.
He was given a jr 6 channel radio, a partially built LT 40 w/tank and all hardware and this new .65 Mutnuc for $150.00. When he asked me if it was a good deal I said, "let me throw up first!" He had never flown but was thinking about it. I had the priveledge of teaching him to fly.

Thanks again for your input.
Spanky