Enrique-F3A

Hello amram. What's new regarding your 175 pump on YS 170 CDI. Any report ?.

Regards
Enrique

Enrique-F3A

Hello Dick,

Could you fix your YS 170 DZ CDI with the new pump. Did it run properly with the new one, is it the 175 pump ?

Regards
Enrique

pattratt

My Feedback: (1)

Enrique
I sold all my glow stuff almost 2 years ago and crossed over to the "Dark Side" and am flying all electric! Sorry I can't help you.
Dick

Enrique-F3A

..

topiwala

Well up till last week my 170 cdi ran fine. Until i had to pull it out of the model and replace a lost needle valve detent. The detent came off due to vibration, sometime during a flight. 

bjr_93tz

There's probably lots of things that could be wrong. I know I oil fouled the spark plug once or twice and it wouldn't clear itself, it would cough splutter and carry on, then you could wind it with the starter with only the occasional pop. Pulling the plug, washing out the oil in the plug, re-installing and restarting the motor upright letting it blow out the excess oil before returning it to inverted was the only cure.

A spark plug won't clear itself like a glowplug if the motor gets an accidental gutt full of fuel/oil.

Or it could be the wire from the hall sensor that was just about broken, and the stress of putting in a new plane was the just enough to break the last strand?

Try to work through one thing at a time...

topiwala

Thanks. Yeah I'll have another go tomorrow and dig into it further. I thought I understood this engine by now!!!!

apereira

Also, flip the prop back and forth when you hear the "click" and make sure fuel with no air comes out of the injector hose(disconnected), let it drip a bit.

Regards

topiwala

Yes it does that fine. Fuel is making it to the check valve no problems. I've looked at the pump and can't find anything abnormal. Changed spark plug. So will give it another run tomorrow and post back. 

topiwala

Well i've now bench run the 170 cdi to diagnose. Two times, the fuel line on the pressure side of the pump burst open right after startng!! That is the first time ever I've seen that happen. Twice!!.

Dave Harmon

Topi....
I had a hellova hard time with mine......same symptoms.
When the silicone fuel line is put on the nipple sometimes a sharp corner will carve out a piece of silicone from the inside of the fuel line. DuBro seems to be worse than other brands.
I reccommend that you remove all fuel lines and toss em'.
Then, remove the needle valve assy from the carb...unscrew the brass body....then back flush the carb housing with alcohol. Flush the body too. Be sure to backflush the nipple on the carb going to the head.
Back flush everything with alcohol...unscrew the top of the check valve on the head and clean up in there...those small silicone pieces are almost invisible and instead of just looking...flush it and blow everything with compressed air.
If it was running ok with the 2 diaphrams...then something happened....try flushing the pump too. The pump is not too difficult to take apart and you may find swarf and debris in there as well.
In addition...there is a piston on the bottom of the pump...you can remove it and flush out in there as well.
Replace all fuel lines....cut to size then flush before installation.
Replace O ring on throt barrel....they leak..

topiwala

Thanks. I'll do all that. and replace all gaskets. Have replaced the spark plug.

apereira

There are some engines with the two diaphragms, one or both is ok, if your engine ran fine, and now it is not, it is better to check the root of the problem, re adjusting the pump will only mask the problem, it should not need that. What you want to do is the most probable cause, changing seals and gaskets, one bad o ring and the pump can go lean to rich in flight depending on your throttle setting and back, flush also as previously suggested.

After many many years of using YS engines I found the best fuel hose for me is the Prather products medium, I have not seen a better hose than that, I replace my hoses yearly, but always inspect the pump reference hose, or simply change it often.

Good luck,

apereira

Double

Dave Harmon

Agreed.....but Prather has been out of business for years....and Aero-Trend that sold Blue-Line has been gone for a long time too.

apereira

Dave,

The Prather line of products is still in production by another company, I think they specialize in boats, I google them last time and bougth two rolls just in case, There are several hobby shops who carry them right now, google it, it is the same thing, hose, quality, box, etc.

Regards

Dave Harmon

Found it....Hyperformance Products.
Great news Al......thanks man.

apereira

Sure! I was happy when I found them.

Regards

allenpl

OK - just to be clear - are people who have no spark plug oiling issues starting the motor with the cylinder upright or inverted?
Regards, allenpl

topiwala

For me. I've never had a spark plug oiling issue. And I always start inverted. Engine mounted inverted in a comp arf valiant. Starts perfect after fueling and priming. However any change to my set procedure of fueling and priming leads to a fussy engine. But that's only on the first start of the day. After that each subsequent start is on the mark. My last little event described I this found was due to a worn/stretched diaphragm in the regulator. Easy fix. All is well now.

apereira

Never had spark plug fouling issue neither.

Regards

bjr_93tz

Yep, happened to me a couple of times now over the course of 2 years.

I ran the engine upright in a big stick airframe first, and used to run the fuel out and put some oil down the throttle barrel at the end of the day. Never had a problem with this until I mounted it inverted in the Aries. On the very odd occasion it just wouldn't "clear" itself for the first start of the day and needed the plug to be pulled. Seemed to coincide with being a bit heavy handed with the oil the previous weekend. I stopped running out the fuel and putting oil in the motor once I'd put 2 and 2 together.

Reassembled the engine with too much oil, and had the needle and reg a touch rich. Ran OK for about 2 minutes until I advanced the throttle then loaded up and died. Again it would start, run but wouldn't clear itself, it got worse until it wouldn't even pop on the starter. I pulled the plug, blew it out, fired first pop then I picked up the plane and held it upside down running while it cleared out the excess oil.

Just a side note, I tend to spend a fair portion of my flying upright, cruising around on part throttle, a 50/50 mix of sport flying and pattern practice. When running 20% oil I found a couple of outside loops with full throttle at the top sorted out any little misfires before they got bad. Running 10% oil has eliminated the need for me to do this. I'd tend to think that if I just took off, flew the F3A schedule and landed again (ie. used the engine for it's intended purpose) then oil fouling a plug wouldn't be an issue.

Another side note, even running 10% oil I changed the plug on the weekend before heading out and after a week on it's wheels the old plug was full of oil. I'm sure it would have started and ran just fine like always, but yep, definitely full of oil...

robert

Has anybody had slight difficulty with the first start of the day with the 170Cdi? What I've noticed is that on the first start it'll run off the prime and then quit, as if it has slight trouble drawing fuel. After a few attempts it will start and from then on it has no problems and runs well. I prime by giving a few squirts of fuel into the carb, and a few seconds spin on the starter before switching on the ignition. Any ideas?

apereira

Hello Robert,

That is normal only if you fly on weekends only, on consecutive days it should not happens, but your priming method might be the problem.

With the ignition off obviously, open the throttle fully, move the prop by hand slowly until you hear the engine "click", then move the prop back and fourth with your hand quickly until you see the fuel on the hose running into the engine, the engine will not be flooded, unless it is done excessively, then go back to idle, ignition and the engine should start immediately.

Check the fuel hoses and the reference hose to the regulator also, this reference hose I change twice a year no matter the condition.

Good luck

Alejandro P.

UKpatternflyer

Hi Robert,

My engines tend to suffer this either when they are very cold and have been left a while as Alejandro suggested. It seems that fuel tends to congeal and block the feed from tank to engine. I guess I could be more dogmatic and drain the tank every time I finish flying for the day and then run the engine dry at low rpm. I can clear the blockage either by heating the engine externally with a heat gun if I'm at home, or by just cranking the engine till I see the fuel flowing up to the injector. The very worst case might need the needle opening up to help the fuel start flowing and then re-setting.

I'm not sure why the fuel congeals. On my test stand in my garage I have a tank permanently fitted and fuel in the pipes always congeals if left for any time so its not like its anything really to do with the engine as such. It does seem much worse in very cold weather. I guess this is just a facet of the oil used; the congealed fuel does appear to be similar to the oil in its un-mixed state; i.e. quite viscous and deep red.

Best wishes

Keith