picard1

My Feedback: (2)

I started my evo 26 this past weekend. First off I could not get the engine to pop with full choke and hand flipping the prop. It took a starter about 5-6 seconds to start up the motor. Next I adjusted the low end for smooth transistion then about 3-3 1/2 min into varying the rpm the motor lost power and died. I let engine cool down and repeted the above steps and at about 3 min in it died again. Any Sugestions?


Mike

DarZeelon

Mike,


Is this a glow version, or a gas version? If glow, what carburettor; Walbro or normal?

Is the engine new, or has it been run in the past?

For a power loss, you must first see this engine make power; then make less power (lower RPM). Have you?


Not enough info...

picard1

My Feedback: (2)

It's a Gas version and it is brand new. Once I opened up the low speed adjustment 1/2 turn the transistion from idle to full power was instant. Plenty of power, then the RPM begins to fall off very fast and the engine dies...

No cowl
18x6
tuned pipe


Mike

DarZeelon

Mike,


Please follow the manual. This engine needs a break-in!

You need to run it at mid-RPM and not at full load from day one...

A test stand break-in is recommended and you will need to use more oil, 3.5-4%, until it has consumed 2 gallons at least.

This engine is designed to last a virtual life-time.
If you abuse it, it obviously will not.

Calm your 'R/C stick fingers' for the first two hours of run-time.
You will only be running the engine on the ground, in stationary conditions during that time.

...Also, a 16x8 prop is better for the break-in, as it produces better cooling with a slightly lower load on the engine.

picard1

My Feedback: (2)

Dar Zeelon,
First off Thank you for your fast response...

I will switch to a 16x8 prop this weekend. Also I am using 87 octane fuel with a 30:1 mix according to the manual. I will run the motor at high idle for 5 minutes then vary the throttle range from 1/2 - 3/4 holding each posistion for a short time for an additional 20 min. It's no problem running the motor on a test stand for several hours so I'll work on this over the weekend. Also I would appreciate any suggestions you may have.

Oh!, I will kick my flyin buddy's out of the hanger- their the ones that wanted to hear that tuned pipe...

Mike

DarZeelon

Mike,


That's what I am here for.

You may want to listen to PĂ© Reivers also.

He has more experience than I do, with the MVVS gas engines.


Never take bad advice from people that only want to hear your pipe...

pe reivers

Thanks Dar.

@Picard1,
The 18x6 prop is OK. It has a low load, and good flywheel action.
87 octane? Way too low. This adds injury to abuse. The engine is of high performance design and needs Europe 95 octane (RON) unleaded (US of A 90 or 91 pump octane), AKA premium leadfree fuel. Apart from the fact that the engine was run at full throttle for too long, you induced knock by running 87 octane. This is damaging to the engine and adds extra heat.
I also have a feeling, that the main needle was set too lean, adding yet more heat that the engine is not yet capable to cope with.
In the beginning, limit all load running to about 2 seconds, and back off to idle after that.
sequence:
Idle 10s, then 1/2, idle, 1/2, idle, 1/3, idle, 3/4, idle, all in short intervals, with idle starting at about 10 seconds, and slowly tapering off in duration during the first hour. After 10 minutes, include full throttle (acceleration only) in the running, but back off immediately again. Do not allow the engine parts to heat up due to friction heat! All surfaces must first match (seat) to each other in order to achieve good smooth running and heat transfer.
Load running (1/2, 3/4, 4/4) can slowly be increased in duration, with no 4/4 load >2s in the first half hour. After about three hours running time, the full throttle runs should reach 20 seconds without any sagging. That is a sign that the engine is partly run in, and full throttle runs can be extended gradually.
It takes about 20 hours running before an engine is completely run in.