| Author |
Message |
    
mikeyb
Member
Username: mikeyb
Post Number: 6
Registered: 02-2014
| | Posted on Sunday, October 16, 2016 - 07:05 pm: | 
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I have a Dispro D-1 engine. It will run on the trailer fine. I've started it many times but I don't let it run long. Once the engine is in the water it will not run. I have the driveshaft disconnected in each case, so there is no load on the engine.
Anybody have suggestions, because it's driving me nuts. |
jb_castagnos
Senior Member
Username: jb_castagnos
Post Number: 1221
Registered: 07-2002
| | Posted on Sunday, October 16, 2016 - 07:42 pm: |
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Is the exhaust below the water line? |
mikeyb
Member
Username: mikeyb
Post Number: 7
Registered: 02-2014
| | Posted on Monday, October 17, 2016 - 07:50 am: |
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No, the exhaust is above the waterline.
Just for kicks after I posted last night I wanted to be sure I wasn't nuts so I went and primed the engine and it ran each time I tried it.
Here is a link to one of the videos I took:
https://youtu.be/-S-goVI_xFU |
david_doyle
Senior Member
Username: david_doyle
Post Number: 80
Registered: 03-2013
| | Posted on Monday, October 17, 2016 - 11:07 am: |
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wow you got a real gem there.
When on the trailer does the fuel system sit at the same angle as when in the water? Does the ignition system behave the same?
From an optimistic point of view I bet a relaxed afternoon with out an audience and no plans to leave the dock would have her purring.
Looking forward to your success. Have fun with it. |
jb_castagnos
Senior Member
Username: jb_castagnos
Post Number: 1222
Registered: 07-2002
| | Posted on Monday, October 17, 2016 - 01:45 pm: |
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Does the exhaust have a dip in it that could form a trap, filing with water when backed in? Try backing it in with the engine running. |
mikeyb
Member
Username: mikeyb
Post Number: 8
Registered: 02-2014
| | Posted on Monday, October 17, 2016 - 06:52 pm: |
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I love idea of backing it in while running. So simple and I never thought of it! I have started it, shut it off and then put it in the water and it wouldn't go.
The only thing that I've thought of is some issue with the water pump, but couldn't figure out why that would cause a problem. |
jim_parrott
Senior Member
Username: jim_parrott
Post Number: 114
Registered: 06-2009
| | Posted on Monday, October 17, 2016 - 09:30 pm: |
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Mikey,
I have had water pump check valves stick, but the engine ran fine in the water just no cooling. Any chance the water pump gasket doesn't have a hole in it, loading up the pump? Is the ignition system working when in the water?
Jim |
johnny
Senior Member
Username: johnny
Post Number: 563
Registered: 03-2006
| | Posted on Tuesday, October 18, 2016 - 07:38 am: |
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I'm assuming when you ran the engine on your tailgate you were not pumping water through the engine.
Then you put the boat in the water and are pumping water through the engine correct?
Sounds like to me you might have a water leak into the combustion chamber? Could there be a internal freeze crack in cylinder or combustion chamber? |
jb_castagnos
Senior Member
Username: jb_castagnos
Post Number: 1223
Registered: 07-2002
| | Posted on Tuesday, October 18, 2016 - 09:16 am: |
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The water pump would have to run for a while before priming, filling the cylinder and drowning it. I still think it's an exhaust issue. I remember my dad repairing an outboard for a customer, ran fine at the shop, wouldn't start in the water. Bees had plugged the upper water-exhaust outlet. When you lowered the motor into the water the pressure would prevent cylinder charge to enter. |
mikeyb
Member
Username: mikeyb
Post Number: 9
Registered: 02-2014
| | Posted on Tuesday, October 18, 2016 - 09:49 am: |
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Ok, so I'm convinced.
I think I need to remove the engine from the boat, put it on it's bed, support the muffler, and run water into the pump while on the bench. This will allow me to check all of the muffler connections when I disassemble as well. |
robert
Senior Member
Username: robert
Post Number: 777
Registered: 07-2003
| | Posted on Tuesday, October 18, 2016 - 11:44 am: |
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Is that kind of wobble in the flywheel common on Dispros? |
jim_parrott
Senior Member
Username: jim_parrott
Post Number: 117
Registered: 06-2009
| | Posted on Tuesday, October 18, 2016 - 02:35 pm: |
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Mikey,
I would first try JB's idea of backing the boat into the water with the engine running already and see what happens. If it dies, put a dry exaust pipe straight in the air and a hose to dump the water overboard and try it again. This will determine if it is your exaust system or not.
jim |
miro
Senior Member
Username: miro
Post Number: 886
Registered: 11-2001
| | Posted on Tuesday, October 18, 2016 - 05:04 pm: |
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I had a similar condition where one day it ran well, and next day wouldn't run worth a damn.
Couldn't figure it out.
So I went to a dry exhaust thinking that the muffler might have had a gob of crud.
Here's the video
https://www.youtube.com/watch?v=Z-eAGV8cbCc
Eventually found the problem - carb setting way way too rich.
Somehow the needle valve moved over time ( several months) and one day as too rich to run.
You might also pull the spark plug, ignition off - and move to flywheel by hand listening for the puff at the spark plug hole as the intake port clears. Give your grease cups a turn to make sure your crankcase is sealed.
Miro |
