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New SV Gassers

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Old 12-07-2012, 07:58 PM
  #876
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Default RE: New SV Gassers

I would think that the WT-433 should have worked out well. If it ran for 20 minutes good and then went all flaky. man that sure sounds like bad fuel, crud in the fuel or something like that. What fuel and oil are you using? I am running the high end synthetic oil from Amsoil, their Saber Pro oil. If you used a low grade mineral oil it could foul the plug out on you. Bad gasoline could do it too. Some of the Chinese cheapie spark plugs do not seem to last very long at all too.

Another thought is the CDI module is overheating. it works until it heats up. Also all of my CDI units so far are rated for 6.0v maximum voltage. A 5 cell Nicad or NMH pack exceeds that and can cause the ignition unit to fail.

I almost forgot that sometimes the little hall effect sensor can go bad to.it may be heat sensitive. I think they have some little test gizmos for it as well as a tester for the CDI too.

A SV 17cc engine I got used had a WT-694 carb on it. That has a 12.7mm venturi in it. When I ran the engine I could not lean it out at all. It stayed extra rich the entire time I ran the engine with it. But I had thought that the 17cc engine needed something around 9mm for a venturi size to work right. So I rummaged through my little collection of carbs and found a WT-520 carb (no choke, but it uses a external primer bulb). So I tried out the carb and the engine ran great with it. So since the engine ran so well then, I put it on a Escapade .60 plane and I have been flying it a lot like that now.

Now my RCV 26cc engine looks quite a lot like a SV 26cc engine too. It has a Chinese clone HiLo carb on it. Hobby king does sell the carbs too.
But you can do like I do and research Walbro carbs with this link here and find a carb with a venturi size of interest and options you want too.
http://wem.walbro.com/walbro/group2.asp?FamilyName=WT


You can see here where the 17cc engine uses a external tube to route the crankcase pulses to the carb's pump cover.



Here is how I took care of the external primer bulb for the engine too.



My RCG 26cc engine looks like a SV 26cc engine. But it uses a Chinese Hilo carb clone of a Walbro.
You can just see how they routed the external pump tube from the engine to the carb's pump cover in this pic here.
They crimped off the external primer bulb line on this carb.




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Old 12-07-2012, 08:09 PM
  #877
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Default RE: New SV Gassers

Neat test stand! Thanks for the info, I suspected the danged carbs all along!!
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Old 12-07-2012, 08:47 PM
  #878
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Default RE: New SV Gassers

Now I have had problems with the diaphragms on the carbs of all of my engines. I have replaced the pump diaphragm with the teflon one. But the black one on the regulator seems to get soft and stretch out after a while, thus it doesn't regulate the fuel anymore. On the NGH engines, they use a soft aluminum pivot arm for the fuel inlet valve and I have had to bend it back up or replace it with a Walbro arm. Usually when the engine suddenly starts to flood out on me, that means the fuel inlet valve has a tiny piece of debris in it, or the pivot arm got bent, or the diaphragm on the regulator stretched out too much on it. I would have thought the diaphragm stretching out would not cause it to flood, But it does. Go figure.

I suspect that there are a lot of fake or counterfiet Walbro rebuild kits out there. That tends to obfuscate the issue too. As the diaphragms may be substandard.


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Old 01-09-2013, 09:56 AM
  #879
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Default RE: New SV Gassers

It has been five years to the first post, and the thread is almost dead now - but I am pretty sure there are a few of these SV engines still surviving. I want to add my experience for posterity's sake.
My first SV was a 26, exceptionally smooth and easy to start engine, not a powerhouse, almost the same power as a DLE-20 - but very reliable - I flew it for over 200 flights on a small fun fly before selling it with the plane. I bought another 26 on ebay, which was identically performing - flew that one for about 50 flights, then the plane crashed - the engine was sold separately later.
I bought a SV-52 twin on ebay, it was a repair project as someone had stripped the plug threads - repaired and flew it on a 85 inch extra for 80 or so flights. Absolute joy to run, first flip starts, never quit and about the same power as a 45cc RCGF engine - Sounds very good at idle and upto 4000 rpm. That engine was later replaced by a single in the airplane, and so it now resides in my display cabinet. It will surely fly many more flights.
I bought a SV-100 version 2 (or 3, as it has DL style cylinders) on ebay last year - It spins a Menz 27-10 at 6100, very smooth, very easy to start, and trouble free thus far - not many flights on it yet, so I will comment on reliability later. It pulls around a World models 36%, 29.5 lb (13.4Kg) Katana with ease, and has plenty of pullout from a steady hover. It has almost the same pull as my 3W-85CS.
video here

https://www.youtube.com/watch?v=Qu2Qi3fKDZ4

All my engines were originally sold by Khurri model engine works in Germany. I never had a single issue with any of these engines, so I would say the engines are more than ok for the price. The only engine I will not recommend is the 17cc single, which is disappointingly underpowered. They are reasonably well constructed, are certainly beefy and thus sturdy, heavier than DLEs and certainly have lower than average power for their size - but they make up for all that in price and ease of operation.
Where would I rate them - well DLE has marched so far ahead of the competition of Chinese engines, I think SV engines would only be a niche engine for the money concious - they are good reliable long-lasting engines, but they can not compete with the newer Chinese brands - (hell, even 3w and DA is having trouble keeping up with these new Chinese brands)
That is my experience with these queer little engines from China
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Old 01-09-2013, 12:04 PM
  #880
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Default RE: New SV Gassers

Well, I think it might depend on the use for a SV-17cc engine as to whether it is a underpowered engine or not. If a user wanted it for 3D or something like that, it would be underpowered. But if you are flying more conventional planes, it has decent power. I have a SV-17cc engine on a Great Planes Escapade .60 RC plane, and the engine works really well on it.  But when you research it some, the 20cc gas engines tend to weigh about the same as the 15cc and 17cc gas engines, and develop more power of course. So going with a 20cc for a .60 size plane is likely the better way to go. Thus it is hard to reccomend any of the 17cc or 15cc engines but instead point the way to one of the 20cc engines instead.
I do like the NGH 17cc engine though. With its front mounted carb, it makes it nice for dropping into a airplane setup for glow engines. It also seems to be more powerful than one might think too. I put it on a huge World SuperStunts .60 plane and it has power to spare.


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Old 01-09-2013, 07:05 PM
  #881
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Default RE: New SV Gassers

I also have an SV100 I just replyed to an another forum and to that I have over 200 flites on a Ziroli 120" AD SKYRAIDER at 52lbs and it pulls that plane around with with alot of guts,50oz tank 2 flites each out,starts easy every time with no problems,all the rest of the engines are ZENS and QUADRAS.it has been a good engine.oh ya a 24-8 4blade beleive it or not.
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