MT 35 Looks Like a Winner
06-12-2010, 10:32 AM
#253
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RE: MT 35 Looks Like a Winner
Removed the MT-35 from my Ultra RC Giles again and plugged the choke air bleed hole with solder. It didn't do any good, this engine still can't be started cold by choking. If I'm remembering correctly, the engine could be choked when the needle valves were initially set at 2 turns open but obviously the plane can't be flown with the mixture so slobbering rich.
Does anyone know if a weak choking action is characteristic of reed valve engines with a rear mounted carburetor? The front of the gas tank is 10.5 inches from the rear of the carb and the carb has no problem pumping fuel from that distance once the engine is running.
I removed the engine again in order to remove the entire choke mechanism since it serves no purpose here other than to block airflow through the carb. My plan is to install a simple device to allow priming from outside the cowl.
Does anyone know if a weak choking action is characteristic of reed valve engines with a rear mounted carburetor? The front of the gas tank is 10.5 inches from the rear of the carb and the carb has no problem pumping fuel from that distance once the engine is running.
I removed the engine again in order to remove the entire choke mechanism since it serves no purpose here other than to block airflow through the carb. My plan is to install a simple device to allow priming from outside the cowl.
06-12-2010, 10:48 AM
#254
RE: MT 35 Looks Like a Winner
There has to be something wrong with the carb or a air leak, with coke on the engine should pull fuel 3 feet straight up.
Have you talked to your supplier about getting a new carb or sending the engine back for them to check out.
Have you talked to your supplier about getting a new carb or sending the engine back for them to check out.
06-12-2010, 06:01 PM
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RE: MT 35 Looks Like a Winner
Thanks for your input. My supplier is actually MT Engines USA and I have seen them post in this thread but so far they have not made any suggestions or offered any help with my problem. Perhaps the proper thing to do is to approach them directly by e-mail.
On the subject of air leaks, there are absolutely no leaks in the plane's fuel system but it is possible that the carb or engine has an unseen leak.
On the subject of air leaks, there are absolutely no leaks in the plane's fuel system but it is possible that the carb or engine has an unseen leak.
06-12-2010, 06:39 PM
#256
RE: MT 35 Looks Like a Winner
Yes, I would email them,
They will not offer to help you or to fix the engine unless you asked them, Just the way they work.
The wheel that squeaks the loudest gets greased first.
They will not offer to help you or to fix the engine unless you asked them, Just the way they work.
The wheel that squeaks the loudest gets greased first.
06-12-2010, 08:50 PM
#257
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RE: MT 35 Looks Like a Winner
ORIGINAL: Rocketman_
Thanks for your input. My supplier is actually MT Engines USA and I have seen them post in this thread but so far they have not made any suggestions or offered any help with my problem. Perhaps the proper thing to do is to approach them directly by e-mail.
On the subject of air leaks, there are absolutely no leaks in the plane's fuel system but it is possible that the carb or engine has an unseen leak.
Thanks for your input. My supplier is actually MT Engines USA and I have seen them post in this thread but so far they have not made any suggestions or offered any help with my problem. Perhaps the proper thing to do is to approach them directly by e-mail.
On the subject of air leaks, there are absolutely no leaks in the plane's fuel system but it is possible that the carb or engine has an unseen leak.
06-12-2010, 09:34 PM
#258
RE: MT 35 Looks Like a Winner
I would call them first, Don't know if the do warranty work for engines they do not sell.??
Tomy, You are on the group right now, you want to try and help to solve his problem.
Tomy, You are on the group right now, you want to try and help to solve his problem.
06-12-2010, 09:44 PM
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RE: MT 35 Looks Like a Winner
Send it to Jodi. He did a fantastic job on mine. He even cleaned it. I am not sure if that's part of their regular service thou.. may want to ask.
06-13-2010, 06:51 AM
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RE: MT 35 Looks Like a Winner
ORIGINAL: BadAzzMaxx
I would call them first, Don't know if the do warranty work for engines they do not sell.??
Tomy, You are on the group right now, you want to try and help to solve his problem.
I would call them first, Don't know if the do warranty work for engines they do not sell.??
Tomy, You are on the group right now, you want to try and help to solve his problem.
He only designs and manufacture engines, he leaves it to the peanut gallery to solve his engine problems.
06-13-2010, 10:18 AM
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RE: MT 35 Looks Like a Winner
Hi guys finally got my engine from the freight forwarders. I haven't run it yet, but am looking forward to it. This will be the first gas engine I run and already I'm having trouble. I can not figure out how to put the throttle and choke linkages on. The choke MUST come from directly behind the engine because of the geometry of the choke arm.
The throttle has to come from off to the side from the rear or slightly in front. Because of the engine mount, I cannot come at it properly from the rear, and I really can't imagine from the front. I have rotated the carb 180 degrees, but have the same trouble. The throttle arm can't be turned 180 degrees because it hits the back of the case. Any suggestions?
The throttle has to come from off to the side from the rear or slightly in front. Because of the engine mount, I cannot come at it properly from the rear, and I really can't imagine from the front. I have rotated the carb 180 degrees, but have the same trouble. The throttle arm can't be turned 180 degrees because it hits the back of the case. Any suggestions?
06-13-2010, 02:07 PM
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RE: MT 35 Looks Like a Winner
Update: Tomy of MT Engines responded to the discussion in this thread about my MT-35 problem and I sent him an e-mail to further clarify the issue.
isaacslaw,
Walbro carbs almost always present some linkage issues when trying to adapt them for model airplane use. Lever arms and gadgets can be obtained from some engine sellers but many folks make up their own riggings. My "Mickey Mouse" setup is shown in the pictures below. Maybe some one else will show theirs. Note that my engine is side mounted.
isaacslaw,
Walbro carbs almost always present some linkage issues when trying to adapt them for model airplane use. Lever arms and gadgets can be obtained from some engine sellers but many folks make up their own riggings. My "Mickey Mouse" setup is shown in the pictures below. Maybe some one else will show theirs. Note that my engine is side mounted.
06-13-2010, 04:26 PM
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RE: MT 35 Looks Like a Winner
PlaneKrazee, tele1974, and anyone else, does your engine have a red sealant that looks like high temp RTV between the crankcase and the back plate? You can see it oozing out of my MT-35 in the pictures in my previous post. Was mine the leaky one or is it standard practice to use sealant at that location?
06-14-2010, 10:51 AM
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RE: MT 35 Looks Like a Winner
Yep mine had the red sealant. I am not sure what is on their now. Mine has the fiberglass reed upgrade now and I am not sure if Jodi put more sealant on. To the newbie.... their are lots of gasser threads for newbies on here and FG so just keep reading. When you've had enough reading and you have thoughly screwed up your motor from reccomendations from other people who also don't know what their doing.... just send it to someone that does know what their doing. Thats what I do anyway.
06-14-2010, 11:19 AM
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RE: MT 35 Looks Like a Winner
tele1974,
It seemed by your videos you seemed to know what's up with gassers. Did Jody also replace the propdriver and or crankshaft?
It seemed by your videos you seemed to know what's up with gassers. Did Jody also replace the propdriver and or crankshaft?
06-15-2010, 05:59 AM
#270
RE: MT 35 Looks Like a Winner
If you look close you can see there is RTV sealant on the back cover, just applied correctly. I did replace the hub but the key way is still not tight enough for my taste, I custom made a key that fits tight, has no slop and can't ride up into the slot cut into the hub, then Loktite the hub on.
There is no engine orcarburetormanufacturer that can/will supply throttle/choke armsfor every application or individuals taste. There are many accessory retailers that sell suitable arms but it's much easier and faster to just make them out of materials that are already on hand. They can be made and adapted to fit any application and direction of travel needed.
There is no engine orcarburetormanufacturer that can/will supply throttle/choke armsfor every application or individuals taste. There are many accessory retailers that sell suitable arms but it's much easier and faster to just make them out of materials that are already on hand. They can be made and adapted to fit any application and direction of travel needed.
06-15-2010, 06:21 AM
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RE: MT 35 Looks Like a Winner
Hub, that's what I meant. It was very nice of Jody to give you a fiberglass reed and a hub machined to match the key in the existing crank to correct the blatent mismatch of original factory parts.
06-15-2010, 10:59 AM
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RE: MT 35 Looks Like a Winner
I believe I have solved my engine's weak choking problem. Three of the four crankcase cover screws were not fully tightened. When I tightened the screws more RTV was extruded. It appears that the engine assembler didn’t put the final torque on the screws.
Before I reinstalled the engine I performed a choking test by connecting a 24-inch piece of fuel tubing between the carburetor fuel nipple and the plane’s tank. With the plane on the ground, I stood up with the engine in my hand and flipped the prop and it did draw fuel uphill with the choke closed just as described by BadAzzMaxx. Also, the fuel stayed in the line until the line was disconnected from the engine.
I ran the engine and adjusted the needle valves and managed to get a maximum speed of only 6660 RPM with a Xoar 19-3DA prop. I’m going to reset the timing to 28 deg. I may have set the ignition timing too retarded because it is difficult do a precise setting with the amount of excessive play that is present in the prop drive key way. I measured as much 4.5 degrees of rotational play between the prop drive and the prop shaft. If I have to remove the prop the ignition timing could shift 4.5 deg when the prop is reinstalled. I mentioned that to Tomy.
Before I reinstalled the engine I performed a choking test by connecting a 24-inch piece of fuel tubing between the carburetor fuel nipple and the plane’s tank. With the plane on the ground, I stood up with the engine in my hand and flipped the prop and it did draw fuel uphill with the choke closed just as described by BadAzzMaxx. Also, the fuel stayed in the line until the line was disconnected from the engine.
I ran the engine and adjusted the needle valves and managed to get a maximum speed of only 6660 RPM with a Xoar 19-3DA prop. I’m going to reset the timing to 28 deg. I may have set the ignition timing too retarded because it is difficult do a precise setting with the amount of excessive play that is present in the prop drive key way. I measured as much 4.5 degrees of rotational play between the prop drive and the prop shaft. If I have to remove the prop the ignition timing could shift 4.5 deg when the prop is reinstalled. I mentioned that to Tomy.