Another frustrating moment with the rotax 912uls

scubarider2 · Post by **scubarider2** » Wed Aug 20, 2008 11:33 am

Well, was really looking forward to a nice peaceful stroll through the clouds at sunset when............I tried to crank her up to get her up in the air and.........NO COMPRESSION :evil: Once again, I can spin the prop with little to no resistance. This time I got in and "bumped" the starter over and over again. Finally she caught....coughed.... and of course was flooded. Waited for about 20 minutes...tried again and bang, fired right up. What is up with this???? :?: Once she fires she runs like a top. I put seafoam in the fuel....I guess next step is to put the seafoam in the oil. Will try that next time I am out.
I just got off the phone with Troy. He suggested that I also put the seafoam in the oil. Run several tanks through and see how it works. There may some connection with the fuel tank residue. I have cleaned the filters and will attempt the seafoam. Will keep everyone posted.
I advise all the new builders out there....RINSE YOUR TANKS THE WAY THEY ADVISE YOU TO DO!
Dennis

DaveU · Post by **DaveU** » Wed Aug 20, 2008 12:11 pm

Dennis,

What fuel are you using?

What power settings are you using while flying? What RPM's do you operate in cruise?

Have you spoke with Dean or another service tech at Lockwood? They are very helpful, as long as you call during the tech support times listed on the catalog. I would be curious to see what they say is the cause.

DAve

scubarider2 · Post by **scubarider2** » Wed Aug 20, 2008 12:42 pm

Dave,
I am using premium auto fuel {mostly} from the BP station here in town. My idle is set at 2100 rpms. My cruise is 5100 to 5200rpms. My static rpms are set at 5300rpms. My climb out is usually at 5300-5400rpms. Troy did say that he talked to the folks at Lockwood and between them figured it MAY be the fuel tanks and the residue stopping the valves therefore no compression. Troy also said I need to get the rpms higher at static so that I can cruise at 5400rpms if I wanted to use the fuel. He got 105-110 indicated cruise speed. I want that. :?
If I continue to have problems I will be calling Lockwood myself, taking your suggestion.
Dennis

taildrgfun · Post by **taildrgfun** » Wed Aug 20, 2008 5:03 pm

If you raise your static RPM you will lose cruise speed. I like my in-flight adjustable IVO . It lets me take off short and have good cruise speed. I just don't think you can have both with a ground adj prop.

scubarider2 · Post by **scubarider2** » Sun Aug 24, 2008 2:49 pm

Ok, I am now thinking that the residue left in the tanks has everything to do with the compression problem. Tar on the inside of the valves is what I believe. I will call Troy tomorrow.
Dennis

b1x4nqb · Post by **b1x4nqb** » Sun Aug 24, 2008 7:06 pm

Taildragger,

What are you getting in cruise vs STOl performance with the IVO?

Thanks,
Paul

scubarider2 · Post by **scubarider2** » Mon Aug 25, 2008 7:42 pm

Ok called Troy and have a battle plan. I am going to use a full can of seafoam in the oil. I am going to run it for one hour at operating temps. I will then change the oil while hot{warm} and filter. I will then put in more oil and filter with 1/2 can of seafoam. I will run it again for maybe less time. Change the oil again with filter while hot. I will then put in the right amount of seafoam with fresh oil and see what happens. If no more compression problems....fixed. If still have problems, Troy told me that he would pack his tools and come to my airport and spend the day pulling the heads and manually cleaning everything out.
As soon as the rain stops here....I will get started.
Will keep everyone informed just in case it happens to you.
Dennis

taildrgfun · Post by **taildrgfun** » Mon Aug 25, 2008 9:20 pm

bl4nqb,
I just bump the toggle switch and get around 5600 RPM to take off short. I really do land in some radical small places often. If I couldn't take off short it would put a HUGE crimp in my fun. It makes a big difference at 5600 vs even 5200. Then when I want to cruise I just bump the switch and put some pitch in it and I can easily cruise 100 true mph at whatever rpm I want at about 5 gph fuel burn.
Even a ground adjustable IVO gives better cruise when pitched for take off than my Kiev prop. I think IVO's look cheesy but they do work good.

Dave Krall CFII SEL SES · Mon Aug 25, 2008 10:42 pm

taildrgfun wrote:bl4nqb,
I just bump the toggle switch and get around 5600 RPM to take off short. I really do land in some radical small places often. If I couldn't take off short it would put a HUGE crimp in my fun. It makes a big difference at 5600 vs even 5200. Then when I want to cruise I just bump the switch and put some pitch in it and I can easily cruise 100 true mph at whatever rpm I want at about 5 gph fuel burn.
Even a ground adjustable IVO gives better cruise when pitched for take off than my Kiev prop. I think IVO's look cheesy but they do work good.

taildrgfun,

Is that the MEDIUM weight Ivo or the Lightweight model? What HP do you figure you have? Thanks in advance.

taildrgfun · Post by **taildrgfun** » Tue Aug 26, 2008 7:13 pm

Mine is the lightweight one. A 72" Patriot model. I think the medium might be better. The annoying thing that the light blades do sometimes is stall a little at full power when I just begin my ground roll. IVO says the wider blades won't do that. I have the 100 hp 912s. If I had the money I would really like to try the medium blades. The light ones are maxed out on the 100 hp.
Actually I figured out how to keep the prop from stalling, all I need is a real big steep hill. Just go over the hill without the engine even running. What a rush. I am NOT recommending this for anyone else to try though. It is not real easy keeping the plane straight without the propwash over the tail, and it would sure be a wreck if I don't keep it straight!
Having so much fun it's a wonder it's even legal!

scubarider2 · Post by **scubarider2** » Sun Aug 31, 2008 8:19 pm

Ok, tried two cans of seafoam in each tank at 5 gallons per tank of fuel. Flew for one hour. Let it sit overnight. Spun the prop with two fingers this morning. Will fly tomorrow morning for another hour with the same mixture. Also ran one can of seafoam in the oil and changed the oil after the hour flight.
So far, lots of money, time and much frustration. I have a feeling nothing will change after tomorrows flight.
Where to go from here..........

Dennis

Jerry · Post by **Jerry** » Thu Sep 25, 2008 3:21 pm

Dennis
I may have an answer for your problem with your compression. Call me @ 815-713-1079 Jerry

Jerry · Post by **Jerry** » Thu Sep 25, 2008 3:24 pm

correction....813-713-1079

scubarider2 · Post by **scubarider2** » Thu Sep 25, 2008 4:05 pm

Jerry, thanks but PROBLEM SOLVED. I rinsed the tanks with $250 worth of thinner. Once the yellow became clear at 3 rinses then filled the tanks with 100LL and several cans of seafoam. Two tank fulls later....FIXED. Fires right up. No compression problems. The seafoam burned out all of it. So now am flying again with confidence. Lesson is, gas does NOT clean the tanks. Clean tanks FIRST.
Dennis

Jerry · Post by **Jerry** » Thu Sep 25, 2008 6:50 pm

Steve, Still give me a call. Would like to talk to you, Jerry

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Another frustrating moment with the rotax 912uls

Another frustrating moment with the rotax 912uls