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Old Jul 29, 2010, 11:11 AM
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Annapolis, MD
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Help!
Magnum .30 4 Stroke: Leaking Valves

Is there any way that I myself can fix this leaking valve problem? Or should I just send it to Global Hobby for repaires.

When I turn it over by hand it doesn't hold compressiong at all and I can hear air coming out of the valves.

Thanks,
GG
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Old Jul 29, 2010, 11:17 AM
Whatever works well .
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United States, MI, Marysville
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Quote:
Originally Posted by Glue Gun View Post
Is there any way that I myself can fix this leaking valve problem? Or should I just send it to Global Hobby for repaires.

When I turn it over by hand it doesn't hold compressiong at all and I can hear air coming out of the valves.

Thanks,
GG
This may be a silly question but still...
Have you tried adjusting the valve lash ?
Please don't be offended. Sometimes a little slip up is overlooked like the adj screw slipping whilst the lock nut is secured. Maybe worth a second look.
Otherwise a little de-carbonizing (clean up) followed by a light toothpaste or Simichrome lapping may help. Check too for a bent valve. A bent valve is easily replaced at home.
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Old Jul 29, 2010, 11:18 AM
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Is this a new engine, under warranty? Or a used engine that has been run some or a lot?
have you run the engine yourself yet?

Have you checked the valve gaps and adjusted them?

if new, it may need to be run-in or broken in so to speak. If it won't run, then it needs to be sent in while still under a warranty.

if old it might be a sticky valve or a worn valve seat. or the valves need adjusting.
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Old Jul 29, 2010, 11:31 AM
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Old Jul 29, 2010, 11:32 AM
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Old Jul 29, 2010, 12:04 PM
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Thanks for all of the responses.

Perhaps I should have supplied a bit more information.

OK. I got this engine back in December. It has been used a lot since. Has seen many tanks of fuel. All of which contained castor oil. It even had a tank or two of E85 and Castor. Some weeks I flew it everyday. It is one of my favorite engines.

Yup I adjusted the valves. Loosened and tightened them. Doing so made no difference. I have never taken the head off, so I don't know if they are burnt or some thing. In fact the only things that I have taken apart on this engine is the glow plug and the valve cover.

Warranty? Well Global Hobby really got me there. The one year warranty is only good if I send in this information card within 10 days after purchasing the engine. I never sent it in.

So there is technically no warranty on my engine.

I'll remove the head and post some pictures if anythings looks fishy.

Thanks,
GG
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Old Jul 29, 2010, 12:44 PM
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Originally Posted by Glue Gun View Post
It has been used a lot since. Has seen many tanks of fuel. All of which contained castor oil. It even had a tank or two of E85 and Castor. Some weeks I flew it everyday. It is one of my favorite engines.
Thanks,
GG
Some four stroke's exhaust valves tend to carbon up with burnt castor, Look into the exhaust port and if you see any carbon build up, that may be the cause.
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Old Jul 29, 2010, 12:48 PM
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I had the exact same problem. I tried everything to solve the problem. Finally gave up and sent it back to Global. They agreed that the engine was beyond repair and sent it along with a new one back to me. Now I have three of them. Never tried the two that weren't run. Wasn't worth the aggravation. I just bought a Saito 30 and solved all my problems. I knew I shouldn't have purchased the Magnum in the first place but I got a "real deal" on them for 60 bucks each. Turned out the one "ran" just like I thought it would so the "deal" wasn't so great after all.

Actually it ran at full throttle quite well but wouldn't idle and was impossible to hand start. No compression causes that.
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Old Jul 29, 2010, 01:07 PM
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Here is a pic:
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Old Jul 29, 2010, 01:13 PM
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iluv2fli:
Yup mine is impossible to start by hand and it has a high idle for a four stroke. So it doesn't look good for my engine. Well I can still try to fix it.

My Magnum .52 four stroke is perfect. Excellent compression. No leaky valves.
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Old Jul 29, 2010, 01:15 PM
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Since you have now taken off the head, I would go ahead and disassemble the valves and keepers. Use some toothpaste and lap the valves. Re-assemble and see if that fixed your problem.

As for Global and Hobby People, they have a great service department and are very generous with their warranty program, card or not.
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Old Jul 29, 2010, 01:15 PM
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I had two like this. I decided to let them sit and rot in my garbage engine pile. I had bought them second hand.

The problem with mine and it seems quite a few of the Magnum 30 RFS is loose valve stem to guide fit. Nothing will make these valves seal.

Greg
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Old Jul 29, 2010, 01:19 PM
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Old Jul 29, 2010, 01:20 PM
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You could try what I did. I lapped the valves using toothpaste and powdered cleanser.It's what I use on my 4 cycles when the valves get carboned up. It takes the carbon off but doesn't remove any metal from the seats. Didn't work on my 30 as the valve wasn't flat against the seat.
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Old Jul 29, 2010, 01:27 PM
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well, if that one valve is rusty, it bodes ill for the bottom end of the engine too.
I would do like Kmot stated and lap the valve into the valve seat some with some toothpaste.
while you have the valve loose you can check to see if the valve guide got clogged up with congealed castor oil or not too.
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