Hi guys,
I have 2 problems and will start with the worst, I have a DT65 that I recently got running and today gave it a good run with the muffs on. After a few minutes the thermostat opened and water ran out the pee hole so I shut it down. I then noticed a small puddle of water on sitting on the cylinder head and a small crack on top of the powerhead.
I have a few options;
1. Try to weld/braze the Ali casting, I know castings are not great for welding, but hopefully a pro can do a good job.
2. Devcon, A friend suggested this which is an epoxy with aluminium fillings.
3. Full part replacement, man that’s a big job.
4. Wreck it lmao I’ve spent a bit of time on her and she’s almost running mint.
Attached is a photo of the crack and a video URL of the of the 2nd problem and a photo of the air pilot screw.
https://youtu.be/8BwpnvTwGsY
2nd problem is fairly minor considering. A few weeks ago I resolved a no spark issue which was a combination of a faulty emergency stop switch, a failed fuel pump and not turning on the ignition when testing with a remote starter. After resolving these issues I had her running for a few minutes and opened the throttle to WOT. When I pulled back the throttle, the engine stalled and wouldn’t start. I thought I would pull the carbies out one by one and give them a clean. The top was nice and clean, #2 had a little gunk and the 3rd had a lot of what I guess is old fuel and a fair amount of corrosion. After cleaning it still would not start so I tested the fuel pump (I had just tested the pump and it was running) which failed due to a split the diaphragm. I had be meaning to do a compression test which came back ok #1 80psi #2 105psi #3 80psi. The first pump had a failed spring so I used the good diaphragm and built one good pump, tested and passed. Engine still wouldn’t start, I knew it had spark (it ran a few days earlier), the rebuilt fuel pump worked and the bowl was filling but wouldn’t pass up the jet and through the Venturi. I squirted some “start ya bastard” in the carbies and she jumped into life and ran (anyone have any insight as to why it took the additive to make her start). After starting the engine would start without the additive.
Now the engine won’t idle, it runs nicely and will idle with the the choke open slightly. My guess is the damaged taper on the air pilot screw Is allowing to much air into the mixture, I’m going to try turning a new taper on the screw (I’m a machinist). It will make the screw seat a millimeter further, or will I have need to make new ones, otherwise i don’t think anyone has new ones in NZ so the next bet is to import from the states.
These are my thoughts and best practices but with input is appreciated.
Thanks
I have 2 problems and will start with the worst, I have a DT65 that I recently got running and today gave it a good run with the muffs on. After a few minutes the thermostat opened and water ran out the pee hole so I shut it down. I then noticed a small puddle of water on sitting on the cylinder head and a small crack on top of the powerhead.
I have a few options;
1. Try to weld/braze the Ali casting, I know castings are not great for welding, but hopefully a pro can do a good job.
2. Devcon, A friend suggested this which is an epoxy with aluminium fillings.
3. Full part replacement, man that’s a big job.
4. Wreck it lmao I’ve spent a bit of time on her and she’s almost running mint.
Attached is a photo of the crack and a video URL of the of the 2nd problem and a photo of the air pilot screw.
https://youtu.be/8BwpnvTwGsY
2nd problem is fairly minor considering. A few weeks ago I resolved a no spark issue which was a combination of a faulty emergency stop switch, a failed fuel pump and not turning on the ignition when testing with a remote starter. After resolving these issues I had her running for a few minutes and opened the throttle to WOT. When I pulled back the throttle, the engine stalled and wouldn’t start. I thought I would pull the carbies out one by one and give them a clean. The top was nice and clean, #2 had a little gunk and the 3rd had a lot of what I guess is old fuel and a fair amount of corrosion. After cleaning it still would not start so I tested the fuel pump (I had just tested the pump and it was running) which failed due to a split the diaphragm. I had be meaning to do a compression test which came back ok #1 80psi #2 105psi #3 80psi. The first pump had a failed spring so I used the good diaphragm and built one good pump, tested and passed. Engine still wouldn’t start, I knew it had spark (it ran a few days earlier), the rebuilt fuel pump worked and the bowl was filling but wouldn’t pass up the jet and through the Venturi. I squirted some “start ya bastard” in the carbies and she jumped into life and ran (anyone have any insight as to why it took the additive to make her start). After starting the engine would start without the additive.
Now the engine won’t idle, it runs nicely and will idle with the the choke open slightly. My guess is the damaged taper on the air pilot screw Is allowing to much air into the mixture, I’m going to try turning a new taper on the screw (I’m a machinist). It will make the screw seat a millimeter further, or will I have need to make new ones, otherwise i don’t think anyone has new ones in NZ so the next bet is to import from the states.
These are my thoughts and best practices but with input is appreciated.
Thanks
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