opjose

I have a new SV .26cc gasser.

I've run about 2 tanks of fuel through it and at first it seemed OK.

Now the high end is fine and so is the transition, but I cannot get the engine down below 3200 RPM.


I've tried setting the needles to 1.5 turns and working in both directions.

Power to the ignition is good.

If I close the LS needle more the engine speeds up to a relatively high rate, even when I have the throttle on the low side.

If I open it up the engine slows down and transitions poorly, but it never idles below 3400 or higher. One click on my throttle trim down, below this, and the engine begins to slow down, stays that way for a second, then starts bogging down and shuts off rather quickly.

I've spent days trying to adjust it with no positive results.

Any suggestions?

Thanks.

SRimer

Does anybody know the timing for this engine, mine came with the ignition set at 45deg btdc, is that normal?

Ken Cz

Hi Guys,
Need some help with my SV-26.

Spent a lot of time tuning and have previously run about 1/2 gas through it on the ground.

No matter I how tune it the transiton is poor - even using 1/16 turn increments and spending hours on it.

In the air at full throttle or nearly full, it has what sounds like a miss???? Could this be timing?

I understand some folks have retarted the timing but I wondering to what degree setting?

Any help on the timing or anything else I can try is appreciated.

Ken

yellowbird911

I can tell you personally I would stay clear of the sv motors. I bought a SV90 motor which was very impressive for about 8 flight until the piston broke which pretty much destroyed the motor. Of course troybuilt who sells the motors does not carry any parts for them so it will have to go back to China. I emailed SV Group and got no response, as expected. I will never buy another motor that parts are not avaliable for, what a waste of over 425.00 dollars. I'm pissed. Just ordered a DLE111, at least parts can be purchased.

opjose

You may need to get a carb rebuild kit and take apart and clean out the carb.

There is also a debris filter in there that can have stuff in it, that may be causing the problem.

opjose

On one hand I agree with you....

I had a SV .26 with over 100 flights in it, and one day the crankshaft split in two after I started the engine.

Now the plane had nosed over with the engine running a few times, so it is possible that this lead to developing a crack in the metal, but that said only Wooden props were used, and I can't imagine that the heavy metal crankshaft should have sheered without first demolishing the props that absorbed all of the damage.

Because of no available parts, I simply replaced it with another identical SV .26, and given the low cost of the motor that was probably cheaper than trying to repair it anyway.

There are other Chinese engine vendors which do provide parts for their engines however.

e.g. HobbyCity/Hobbyking tends to have all sorts of parts for their engines and I have successfully used their carbs and ignitions on other engines.

blhollo2

My Feedback: (278)

anyone know what type of spark plug the sv26cc engine takes???

opjose

CM-6

blhollo2

My Feedback: (278)

no it is not a cm6 plug

opjose

Mine is.

blhollo2

My Feedback: (278)

on your sv26cc?? calls for a NGK BPMR6F spark plug...

rebranger

That's the correct Plug, now does any one where you can get it? I have tried to cross reference it to an Autolite, Champion, Bosch to no avail..all I can find is NON resistor types & they WILL not work! Too much interference! Help Please!

w8ye

My Feedback: (16)

Champion: RDJ8J

mrbigg

My Feedback: (21)

ebay. Tried finding the champion around here and could only find the non resistor versions. Ordered a bunch a while back so I'm stocked up.

w8ye

My Feedback: (16)

I only use NGK or Bosch. Champion is not what it used to be.

I havn't used Champions in 10 years but I always had to order the resistor ones. They always came the next day. I got them at NAPA.

The local Advance Auto stocks the NGK BPMR plugs but not CM6. The next fartherest away (7mi) Advance Auto stocks the CM-6 plugs. O'Rielley's is cheaper but you get them the next day.

rebranger

I guess this thread has died..like all The SV engines & suppliers..

earlwb

The engines pop up from time to time on Ebay, etc.  I think they are called RCS engines now as I have seen what look like the same engine being sold under that brand.  Hobby King is selling the RCG 26cc engine which looks pretty much identical to the SV  26cc engine.
I remember seeing a Canadian online store selling SV engines earlier, but I haven't located it yet.

rebranger

Mine (I bought 6 from Troy Built Models, TBM) all ran eventually!  LOL, one had a pluged charge port out of the crankcase, one had a stopped up hi jet, ALL need timing adjustment & plug change, NKG or Bosh resistor type, I sold all but 2 of them mounted on planes (warbirds) & still have two left. One is on a CG YAK, other for a spare.  The carbs that come on them will work, i.e., they'll run, but they run better if you put a REAL Walbro on 'em. 

dadragon

I got my SV100 from troybuilt in 08 I think,when they had their last one up for sale I missed it buy a few days,I have had very good performence with this engine,it is mounted in a 120' Ziroli AD skyraider,48lbs and pulls it to the max(no 3D)flying scale.I can not find any other HBS that carries them,there is a site in mainland china I'll have to look for it and get back with it.OH YA I am running 100LL avgas and 35:1 penz air cooled at 6100' alt for 3 yrs.no problems.

dadragon

Here we go www.aliexpress.com-store-602744 try that one guys.

earlwb

Here is one of the Canadian stores that sell them.
http://www.amr-rc.com/index.php?path...rque&langue=en

rebranger

 I have several SV-26's that I have never been able to get to run right. I have reset the timing, put FULL kits in the carbs & in order for them to run at all I have to open the hi speed needles about 3 + turns!! Mine came with chokes.

dadragon

the BPM plug is longer than the CM-6,but remember to change over you must also change the caps.CH-ignition carries a kit to do so,I had to change over on my SV100,instruct sheet comes with it.and in my case going from a long reach to short I had to machine .015 off the plug seat base of the heads so the spark would not arc out on the head.just a lil more info,the engine runs perfect.

earlwb

Some of the carbs get their pulses for the pump from a internal hole or passage routed up through the base of the carb. Other engines may run a short tube proividing pulses from the crankcase to the carb base adapter or heat block plate/spacer for that purpose too. Then some engines run a tube from the crankcase to a fitting on the pump cover to provide it with pulses.

The most common problem is getting the base gasket reversed blocking off the pulse passage sending pulses to the pump. That is on those carbs using this method. If the engine uses a short tube going to the base of the carb or mounting block, then it might have the same problem too.

For the external method, you need to re-use the pump cover with the fitting on itand move it tothe different carb or install a new fitting on the new carb;s pump cover.

Now then some carbs come with no choke. But they may use a external primer bulb or they may have the primer bulb built in too. Some carbs may be setup with both too. I did it to myself too, but it is easy to route the fuel line to the wrong fitting on the carb where you have both a external primer bulb and a fuel inlet fitting. I sort of like a primer bulb versus using a choke.

The carb on my example engine was working Ok. But I'll look later and see if I can come up with some other suitable carbs one could use too.

Oh yeah, one other thought it the Reed valve unit might have a problem and not be closing correctly or closing good. So maybe checking out the reed valve for flashing or other things that might prevent it from closing or opening correctly might be worth a look see.

The gaskets on the base of the carb and reed valve block have been known to leak too. Usually the rule was to always replace the gasket if you pull the carb off. It is a easy air leak to get and a easy fix too.

rebranger

Thanks Earl,