Berwyn Bill

My Feedback: (16)

Hey Pe,

I have an older MVVS 35 that's giving me trouble (Vlach ignition type, all silver head). It seems to be flooding out really easily and then it's next to impossible to start. I've been tinkering with it to no avail so I'll run down my starting procedure and if anything seems wrong, please let me know. Also, any troubleshooting would be appreciated. Engine was starting fine a couple of weeks ago. Now it won't start.

MVVS 35 w/ Vlach Ign
MVVS Pipe
91 Octane (USA) with 50:1 synth oil
Brisk UR17 and Champ DJ7J plugs
Bambula 20x8 prop

1. Choke on/Ign off - flip until gas gets to the carb
2. Choke off/Ign on - Flip until it starts

That's what used to work. Now the only way it will show any life is if I

1. Choke on/Ign off - flip until gas gets to the carb
2. Choke on/Ign on - Flip until it "burps"
3. Choke off/Ign on - flip until it starts (but then it dies after 1-2 seconds)

I've taken out the plug and blown it dry and spun the engine until it cleared when it flooded. I've checked the ignition with the plug out and it sparks correctly when the prop is turned. The spark is a little better with the Camp plug (it's newer) but the problem persists. The fuel mix is about two weeks old. The engine is side-mounted on a large profile. I'm just about at sea level and the air temp has been anywhere from 50 F to 80 F.

I think I'm missing something simple here. Any suggestions would be appreciated. My other gas motors seem happy with my starting technique and fuel, just my MVVS that's not wanting to fly. [&o]

Thanks,
Bill

pe reivers

procedure is:
choke on, ignition ON (ON)
flip til it starts and stops or burps
choke off
flip til start

If you do not start at first with ignition on, you will never know when the engine gets fuel, and it is easy to flood your engine if the idle needle is set rich.
basic idle needle setting: find best idle rpm by adjusting the idle needle. Then open up the needle 1/4 turn.
after any idle needle adjustment, the high needle must be adjusted as well.

The champion DJ7J is not good, you need a resistor type plug like NGK BMR6F

Berwyn Bill

My Feedback: (16)

Thanks Pe. I'll try to find that plug. The Brisk UR17 still puts out a spark so I'll go back to it.

I've tried on a couple of trips to the field to start it using the procedure you stated. It will burp with the ign on and the choke closed and then I open the choke and keep flipping. Usually there's just no response. A few times the motor has come to life just to die after about 1-2 seconds. The needles are just where they were set when I got the engine from the previous owner and the times I flew it, the engine seemed a bit rich but not extremely so. I did try leaning the low end needle to try to help with the starting but it didn't seem to make a difference.

I tried it today like this but still couldn't get it to start for more than 1-2 seconds:

1. Choke on / ignition on
2. Flipped it until it burped (usually 4-5 flips past where I saw gas making it to the carb fuel inlet)
3. Choke off
4. Flip anywhere from 5 to 25 times before it comes to life and then dies after a couple of seconds.

The throttle plate is open for what was a good idle when I could get it to run before. I've experimented with a bit more and a bit less throttle but the results seem the same. I'm starting to get the idea there's something amiss in my carb. When it dies, it sounds like it's just not getting fuel.

What is the stock low end needle setting, so that I have a benchmark to work with (in turns out from closed)? It's tough to tune it with the engine running if you can't get the engine to start. If you could give me an example of some god needle settings for me to start from scratch with, I could at least know that my needles aren't stopping me from getting it started.

Thanks again for the help. This engine is great on the plane (OMP 79" Yak profile) and I'd just like to get it flying again.

Bill

pe reivers

low 1.5, high 1.5 should get your engine running for tuning. See my forum http://prme.nl/forum/viewtopic.php?t=10 for details.
Clean the carb filter: look inside below the cast carb cover for the strainer. It should be clean. If not clean, also check your total fueling setup. No dirt should be allowed to enter the fuel suction line. The carb strainer is a last resort, and is not meant to filter the fuel. Use a felt clunk in the fuel suction line.
Check the carb pulse line connection to the crankcase. It must be secure.

Berwyn Bill

My Feedback: (16)

Thanks Pe.

I replaced the pulse line to the crankcase, it was a bit stiff and aged. The carb strainer was clean but the diaphragm seemed a bit stiff upon inspection. I'll leave it as is and reassemble to give it another try today.

Bill

pe reivers

You should replace the diaphragms as well. They should be very supple. It's a WA10 replacement set.

the Wasp

My Feedback: (1)

hope it's OK to post !!

can he use a 5 cell pack ??, a 5 cell made a night and day difference in starting my Read Head with the Vlach Ign

pe reivers

Do'nt know. The US Vlach is not the same as ours.

Berwyn Bill

My Feedback: (16)

Pe and all who posted and pm'd,

Thanks for all the advice. I took off the carb and broke it down. Once I had the diaphragm free of the unit, it seemed in pretty good shape so I remounted it. I re-assembled the carb and went back to the old UR17. Then i took it outside to the garage:

1. Ign on/Choke closed - about 5 flips after the gas got to the carb, it burped nicely.
2. Ign on/Choke open - About 6 flips and it sprung to life and ran like a champ!!!!! [sm=biggrin.gif][sm=thumbup.gif]

I set the needles and ran it for a bit and then shut it down and restarted it a few times just to make myself happy. Whatever was happening seems to be fixed. I'll take it out for some flying tomorrow!! Thanks again!!!!!

Bill

pe reivers

You're welcome.