OS 91HZ-R problem

[LFRyder]

Guys,

I recently purchased the OS 91 HZ-R conversion and I have not had much success with it. Okay, more like no success. I have my needles at stock settings but fuel will not enter into the motor. I can't figure it out. I have tried new lines, new clunk, cleaned the carb - just to eliminate as many possible causes as I could.

I am not completely convinced it is a problem with the carb though because I can connect a fuel line to it, cover up one end of the carb and breath in on the other side and fuel enters. When I connect it to the engine, I can keep the starter on it indefinitely without any fuel entering. I have taken the engine apart and everything appears clean without any scoring s/p? and it has been put together correctly.

The only thing I can think of is that my starter is not turning the motor over quickly enough to build up negative pressure to pull the fuel in (using drill to start). Do you guys think this is the problem? I am needing some help. Thanks guys

Matt

[ualdrivr]

Matt, is your installation correct?

http://manuals.hobbico.com/osm/osmg4039-manual.pdf

This is the PDF from OS, I'm sure you have the same one that came with the kit. Is the one way valve properly installed, direction is critical for that valve.

Check everything and double check.

Let us know.

[Steve Graham]

Hey Matt,

I just put this carb on my motor. Somethings gotta be wrong, broke, plugged, leaking etc but you already know that by now.

When I spin the motor with the starter fuel flows immediately. I would double check the orientation and location of the check valve as UALdriver suggested. You could also check the check valve by ensuring that you can only blow through it in one direction. I suspect this thing is using some sort of diaphragm that could have been damaged in the factory somehow. This setup generates so much head pressure in the tank that it sounds like someone opening a slightly shaken beer when I pull the vent line for refueling even 10 minutes after flying. My understanding is that fuel is more pushed by this pressure to the regulator than pulled by any sort of Venturi related vacum.

Steve

[J-S-Q]

Originally Posted by LFRyder

The only thing I can think of is that my starter is not turning the motor over quickly enough to build up negative pressure to pull the fuel in (using drill to start). Do you guys think this is the problem? I am needing some help.

Whilst it could be a possibility that your starter is the problem, I've noticed that even when my starter was turning the engine over pretty slowly due to a partial hydro lock, it still easily built up pressure in the tank. As WW Corrigan says above, this engine really creates quite a high tank pressure. You'll be able to tell if the tank is pressurising ok because when you release the vent line from the tank you should hear an easily audible rush of air exiting the tank.

[LFRyder]

Thanks for the replies. I am definitely pressurizing the fuel tank. The problem is not creating the negative pressure to actually suck the fuel into the motor. I tried starting this afternoon and even completely took the needles out and there is no fuel coming through the carb at all.

From what I was told on runryder, the HZ-R is more of negative pressure pulling in the fuel as compared to fuel tank pressure pushing fuel into engine. Is that correct?

[chuckk]

when you run the starter is fuel getting to the carb from the tank?

are you turning the starter in the right direction? counterclockwise? sometimes we have brain farts.

is your carb at the idle position or slightly more open when you start?

is your fuel line clamped?

[LFRyder]

Yes starter is turning over correctly in CCW direction. Fuel lines are open and if i take the line off of the carb, it flows out very quickly.

I have tried bringing in fuel at all carb positions, slightly open, 50% throttle, 100% throttle. Nothing from any position. Acts exaclty the same.

When I fill the fuel tank up and turn the starter over a few times, fuel will eventually reach the carb in the lines, but after that, it seems like it is not getting pulled through the carb into the engine.

Any more ideas? Possibly the starter not turning over quickly enough?

[chuckk]

in the first post you mentioned using a drill.

i used a drill for 2.5 years on my 600N without a problem. when i bought my first 700N i used the same drill with my .91 HZ-PS. I had very mixed results. usually the engine wouldn't start. i quit using the drill after about 4 days and 3 snapped start shafts.

maybe a true starter will solve your problem.

this is the drill that would start a .50 but rarely a .90.http://www.ridgid.com/Tools/R92008-F...l/EN/index.htm

[LFRyder]

Chuckk,

I am hoping that this is the case. At this point, I don't know what else I can really change other than the whole engine. My new align starter will be here on Friday so hopefully that will be the problem. Im crossing my fingers.

[Steve Graham]

Matt,

Pressure is a differential, much like voltage. It is a motive force that will get results unless you have a blockage. The point is pressure and suction make no difference they are the same thing as far as the fuel in your lines is concerned. As to the question of the carb generating a vacuum in order to pull fuel in the only mechanism I'm aware of to facilitate this is the Venturi in the bore and I don't think this creates a very large draw, just enough to feed the engine. No where close to the probably almost 10 psi the crankcase pressure gives you.

You stated that you see fuel actually enter the lines and fill them up to the carb but after that there is no more fuel drawn in. Are you sure? Once the lines are full of fuel I don't think you can to see it moving through them. This leads me to the possibility that you somehow ended up way flooded. Are you getting any hydro locking?

Another possibility I can think of is that somehow in manufacture you got a carb with an internal defect like a blocked passage or bad O ring that doesn't seal?

Hows the plug?

The theory behind carbs and internal combustion is fairly simple. Air, fuel and fire in the right quantities at the right time. The hard part, for me anyway, is in actually determining which one of the 3 is wrong.

I would definitely call OS and tell them what your experiencing. I e-mailed them and they did get back to me. They didn't really solve the problem for me but you most likely have a different problem that hopefully they will have some ideas on. Hang in there you'll get it going eventually.

Steve

[Goodlett]

My recently converted HZ-R did the same thing after it previously ran great. Fuel would not enter the carb no matter how long I spun the starter. I finally determined the check valve was stuck closed. I took the check valve off and sucked and blew through it and it freed up and the engine has run great ever since. Also if the check valve is installed backwards it won't run.

Glenn

[LFRyder]

WW, I really appreciate your help. I called OS and they agreed that it is more than likely the starter not generating enough suction. They honestly weren't that helpful over the phone though, just seemed to agree a lot on my theories.

My whole process once I put the fuel into the tank is this:
1-fill fuel tank
2-open up lines (at this point the line running from the tank to the carb has fuel about 7/8 of the way to the carb. Right at the carb though is a small pocket of air)
3-open up throttle to around 50%
4-apply starter
(air to the carb is removed so fuel completely takes up the line to the carb)
5-light glow plug but never cranks

This is where the whole system begins to fail. I can continually turn the starter over without any kind of fuel going through the carb. There is no fuel getting into the engine or the muffler. The system will not hydrolock because of the lack of fuel. To release the pressure that the fuel tank is building, the system begins to leak at the entrance to the regulator. I have tried 3 different glow plugs, 2 x OS 8's and an Enya 3. It doesn't seem to matter. Does it sound like I am doing anything wrong? Glow plug IS WORKING.

Also, with the reg, I can't blow air through the reg at all but if I suck in air from the carb, then the diaphragm opens and allows air in. So it does seem like the whole system focuses on sucking the fuel in rather than pushing it in. As for is this the way it is supposed to work, I am unsure.

Thanks guys for your help. I really appreciate it.

[chuckk]

have you tried bumping the throttle trim up 4 or 5 clicks during starting? if by some chance fuel is making its way through the engine it might have filled up your pipe. take the exhaust off and see if fuel pours out of the pipe.

[LFRyder]

I have taken the pipe off multiple times with this carb and there is no fuel in the pipe or engine.

[LFRyder]

Goodlett,

The check valve is clear and in the correct direction. I am building tank pressure just fine. I am getting a new starter in the morning. Wish me luck

[ualdrivr]

Originally Posted by LFRyder

My whole process once I put the fuel into the tank is this:
1-fill fuel tank
2-open up lines (at this point the line running from the tank to the carb has fuel about 7/8 of the way to the carb. Right at the carb though is a small pocket of air)
3-open up throttle to around 50%
4-apply starter
(air to the carb is removed so fuel completely takes up the line to the carb)
5-light glow plug but never cranks
.

Why do you open the throttle 50%? Is that a procedure spesified in that engines manual, for priming?

I have the 91-HZ and all I do is crank the starter a few times until I get fuel in the line to the motor, after that I introduce ignition, but all that is happening with throttle at idle maybe a few clicks up on the Throttle trim for just a bit more idle power.

The motor starts right up after a few spins of the starter and when it worms up I come down to my idle setting and that's it. Maybe you are hydrolocking the motor. How is your glow plug? Does it get power? Does it glow?

[LFRyder]

UAL,

It is called for to prime the motor in the manual. It says full throttle but i have read that 50% throttle works better in a couple of thread. I have tried every different way to prime it and no fuel ever enters the motor. I am not hydrolocking. I can keep the starter going indefinitely and no fuel enters. the starter never stops turning the motor. Glow plug gets power and is glowing bright orange

[Goodlett]

I have noticed my converted engine is more difficult to start only on the inital start of the day. In fact, a few days ago, I gave up with the align starter and used the Dynatron. Since then I've learned to just be more persistant with the align starter. You might try squirting a little juice directly into the carb and see if it fires. If it runs then dies my guess would be a clogged or defictive carb. I usually spin mine for 5 to 10 seconds at full trottle before igniting the glow plug.

Good luck and keep at it. In my opinion the conversion is well worth the money once you get it dialed in.

Glenn

[Steve Graham]

Yesterday I went flying.

The engine needed a few more attempts to start than it had previously required.

After starting I noticed some bubbling on the top surface of the fuel in the tank at idle. I don't recall having seen this before.

The engine seemed to be running fine so I took off and got about one minute in when she flamed out.

The auto going downwind and about 100 yards away resulted in only a slightly bent tail boom.

The engine was quite hot when I got to it. When I pulled the tank vent line there was no pressure in it. Cranking the engine generated no pressure through the check valve.

I pulled the check valve and attempted to blow through it without success which I was able to do before I installed the new carb.

Right now I'm soaking the check valve in alcohol. I suspect that it got some dried fuel in it that acted to glue it shut? I will report back when I get more info.

Matt, are you able to blow through your check valve?

Right now I'm really frustrated at having spent good money after bad with OS. The real problem I have with this company is their general neglect for the consumer in terms of support after the sale. Seems like there would be an opportunity in the marketplace right now for a manufacture that wants to actually support their customers.

[ualdrivr]

Originally Posted by W.W. Corrigan

Yesterday I went flying.

The engine needed a few more attempts to start than it had previously required.

After starting I noticed some bubbling on the top surface of the fuel in the tank at idle. I don't recall having seen this before.

The engine seemed to be running fine so I took off and got about one minute in when she flamed out.

The auto going downwind and about 100 yards away resulted in only a slightly bent tail boom.

The engine was quite hot when I got to it. When I pulled the tank vent line there was no pressure in it. Cranking the engine generated no pressure through the check valve.

I pulled the check valve and attempted to blow through it without success which I was able to do before I installed the new carb.

Right now I'm soaking the check valve in alcohol. I suspect that it got some dried fuel in it that acted to glue it shut? I will report back when I get more info.

Matt, are you able to blow through your check valve?

Right now I'm really frustrated at having spent good money after bad with OS. The real problem I have with this company is their general neglect for the consumer in terms of support after the sale. Seems like there would be an opportunity in the marketplace right now for a manufacture that wants to actually support their customers.

Steve, WTF is going on buddy? Is there a problem with your setup or is there a problem with the upgrade from HZ to HZ-R? Plus that comment of yours, that the engine was hot when you got there, I don't like, that means that it ran lean for a while before it quit. I spoke with Bert Kammerer on allMyRC.com on the subject of the -R motor and he said he loves it, but mind you he had a new motor from OS not the upgraded HZ motor like you do.

Maybe there is a problem with the upgrade, I don't know. Go to that forum and post something on Bert's sub-forum, maybe he has some words of wisdome about your problem. Bert is always helpfull with everything and he is glad to answer questions, or you can ask him directly at SmackTalkRC.com or his own sight BertRC.com.

Hope this helps.