Author Topic: 1st I.C. build "Tiny"  (Read 43932 times)

Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #375 on: December 03, 2017, 12:24:24 PM »
Well, I finished up the little stuff yesterday and rigged up the ignition.  No joy.  Not even a pop.  I stayed up very late trying to see a glimmer of life; but, there was none.  I'll keep trying.

-Bob
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Online b.lindsey

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Re: 1st I.C. build "Tiny"
« Reply #376 on: December 03, 2017, 01:46:21 PM »
Frustrating I know Bob. Just be methodical....is it getting fuel, is it getting spark, and is it getting compression? Are you trying to start it by hand or with a starter?

Bill

Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #377 on: December 03, 2017, 03:41:07 PM »
I'm not really frustrated Bill.  I didn't expect it to run right off the bat.  I'm disappointed that it didn't even pop.  It is getting fuel and spark.  I'm not happy with the compression.  I'm going to make a head gasket because I have fuel bubbling from under the head.    I pulled the head off last night and placed my finger over the cylinder.  It was okay; but I might add an O-ring if the head gasket doesn't help.  I'm probably also going to switch over to pump gas.  So far, I have been trying Coleman fuel with two stroke oil.

-Bob
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Offline gbritnell

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Re: 1st I.C. build "Tiny"
« Reply #378 on: December 03, 2017, 04:57:23 PM »
Bob,
I use pump gasoline with 2 cycle oil at 50:1. I found the best way for the initial start is to leave the needle closed and while turning it over with an electric starter of some sort slowly,and I mean real slowly, start opening the needle valve. If that doesn't do it then look at other elements, most likely the compression which could also be valve sealing. With good compression they start up by hand once the needle valve is close to where it should be.
gbritnell
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Online b.lindsey

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Re: 1st I.C. build "Tiny"
« Reply #379 on: December 03, 2017, 06:05:30 PM »
Bob as you recall, I went the o-ring route as well and found that helped a lot. The electric starter George recommended also helped to get thing sorted out. Now it will hand start, but the needle valve setting is sensitive or at least mine is. You will get it I know  :ThumbsUp:

Bill

Offline Tonyr

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Re: 1st I.C. build "Tiny"
« Reply #380 on: December 03, 2017, 06:17:52 PM »
Bob,

I use a sewing machine motor screwed to a board, with a belt to the flywheel as a starter.
You can operate the motor with the foot pedal.
This leaves both hands free to adjust the engine.

Tony

Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #381 on: December 03, 2017, 06:29:58 PM »
Thanks George.  I took the head off and checked the valves on the test fixture.  When I used my MityVac switched over to psi it popped the line off of the nipple on the fixture.  At this point I still believe that the valves are sealing well.  I think the Coleman fuel at 30:1 is not helping.  Pump gas at 50:1 should be a bit more volatile to get it going.  I have been turning it over with a drill.  I will do the mixer adjustment as you describe.

Thanks Bill. It will eventually run.

That's a great idea Tony.  Unfortunately, I don't have that arrangement handy.

-Bob
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Offline Sleddog

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Re: 1st I.C. build "Tiny"
« Reply #382 on: December 03, 2017, 08:40:19 PM »
There are far more knowledgeable people here than me.

I had trouble getting my 1st IC engine to run, an Upshur. I too am using an SS ignition. The instructions said to install a resistor (supplied in the kit) in the spark plug wire. I did. I was having no luck getting the engine to run. I called Roy & he suggested taking the resistor out....I did & that's what it needed to run.

Just a thought.

Jack

Offline gldavison

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Re: 1st I.C. build "Tiny"
« Reply #383 on: December 03, 2017, 11:43:06 PM »
Hi Bob,
 When I built my tiny I got really frustrated trying to get a perfect valve seal. I redone the valve seats three times and I made three sets of valves. I finally give up on a perfect seal. They do leak some, but it is running and starts easy now.  I also used an electric starter to get it running, and as George says that needle valve is very sensitive. I have found 5 degrees either way of center after I got it tuned it will not run.
I'm using aviation gas in my engines with a 60 to 1 ratio of Marvel Mystery oil and it seems to work really well.
I am sure you will get running.

Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #384 on: December 04, 2017, 01:09:49 AM »
Thanks Jack.  I already have tried it with and without the resistor with no effect.

gldavison- At this point, I do believe the the valves are not the problem. Did you use a lapped piston or an O-ring?  After what both you and George have stated, I believe the 30:1 Coleman fuel is not a plus for an initial start.  I'll have to get some fresh gas and try tomorrow along with the slow turning of the mixer screw.

-Bob
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Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #385 on: December 06, 2017, 02:47:00 AM »
Getting a little closer. 

Switched to pump gas at 50:1.
Ditched the drill as a starter  I have a printer motor hooked up to a pc power supply.  I can now hear what is going on. 

It seamed to have a little life in the form of some weak muffled pops here and there.  Nothing significant, but something.

I'm going to try it tomorrow one more time.  If it doesn't run then, I will add an O-ring.

I know I need a 3/8 od O-ring.  I would guess Viton would be the preferred material.  What is a good cross section diameter?  Can I buy them at an auto parts store?

-Bob



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Online Kim

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Re: 1st I.C. build "Tiny"
« Reply #386 on: December 06, 2017, 05:30:27 AM »
Bob,
You can get one of those little box sets of assorted sized of Viton O-Rings from Harbor Freight:

https://www.harborfreight.com/180-piece-viton-o-ring-kit-67525.html

Kim

Online Roger B

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Re: 1st I.C. build "Tiny"
« Reply #387 on: December 06, 2017, 09:05:04 AM »
Have you checked/experimented with the inlet valve spring? Others have found small hit and miss engines to be very sensitive to this. If it is too strong you won't get enough mixture into the cylinder.
Best regards

Roger

Offline 90LX_Notch

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Re: 1st I.C. build "Tiny"
« Reply #388 on: December 06, 2017, 11:26:54 AM »
Thanks Kim.  Unfortunately, the nearest HF is over an hour away. I'll search local auto parts stores first.

Rodger, you must have read my mind.  I was laying there last night trying to fall asleep when the intake spring crossed my mind.  I had made several and tested them and the one that is installed is the lightest that opened under vacuum yet didn't leak. I think I still have some of the other springs around to try.

-Bob
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Online b.lindsey

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Re: 1st I.C. build "Tiny"
« Reply #389 on: December 06, 2017, 12:19:54 PM »
Sounds like a little progress Bob. I had thought about the inlet spring also but it takes very little movement in the valve to let the fuel into the cylinder. Honestly I have looked...and have yet to even see the inlet valve moving even when the engine is running. I know it is or the engine wouldn't be running but it did surprise me some. Hang in there you will get it. My bet is on compression and I do think the o-ring will help if not solve the problem.

Bill