imported_KLR
Cadet
- Joined
- Jun 28, 2006
- Messages
- 16
I need some advice as I am new to boats and outboards. If anyone could point me in the right direction I would SOOOO appreciate it.
-- please forgive terminology mistakes, Im learning --
From the beginning.....
I just bought a 1973 Thunderbird Trihull with a 1973 Johnson 65 HP outboard (original engine?)
Engine's history as I know it......
Last owner used the boat quite alot and had trouble last fall with the cooling system. He found out on the lower drive part of the outboard there is a tube (about 3/4" x 4") that I assume routes the water from the inlets up to the engine(?) had come loose and water was leaking into the lower drive unit and there was a loss of cooling, the engine suffered damage to #2 cyl.
A marine shop did the repairs last October which included.....
Bored cylinders .020 over and rebuilt the whole engine,
rebuilt the carbs,
tuned the engine,
checked the ignition system, fuel system & everything else.
The boat ran BEAUTIFUL for 4 months till the lower unit went out one day and the boat lost forward & reverse.
The lower unit was replaced and now I bought the boat and cant get it to start.
It will fire up soon as you hit the key but dies in about 2 sec.
If I stay at the engine while someone cranks it and play with the choke & hold the throttle about 1/2 way open it will start and run rough for about 20-30 sec. It appears to be flooding bad and a small amount gas does run out the opening of the caburators. When it does start and run for the 20 seconds it bogs bad and barely runs till it dies.
I thought the floats might be bad or adjusted wrong but they were new and set right. I ran a compression test today and all 3 cyl were EXACTLY 100psi.
Timing is perfect
compression is good
spark is good
carbs are SUPER clean & float is set right
fuel pressure is good
What am I missing?
What would make the carbs leak gas out of the venturis?
What could be making it run SOOO rich & flood out?
I am thinking now that the reed valves may be trashed. The engine was 33 years old and after the rebuild maybe the higher compression cracked or destroyed the reed valves, That would cause the poor running as very little fuel/air is getting into the engine & also with every down stroke of the piston instead of compressing the fuel / air mixture it would blow it partially back out the intake and carbs. Maybe? what do you think?
Any help would be appreciated
Mike
-- please forgive terminology mistakes, Im learning --
From the beginning.....
I just bought a 1973 Thunderbird Trihull with a 1973 Johnson 65 HP outboard (original engine?)
Engine's history as I know it......
Last owner used the boat quite alot and had trouble last fall with the cooling system. He found out on the lower drive part of the outboard there is a tube (about 3/4" x 4") that I assume routes the water from the inlets up to the engine(?) had come loose and water was leaking into the lower drive unit and there was a loss of cooling, the engine suffered damage to #2 cyl.
A marine shop did the repairs last October which included.....
Bored cylinders .020 over and rebuilt the whole engine,
rebuilt the carbs,
tuned the engine,
checked the ignition system, fuel system & everything else.
The boat ran BEAUTIFUL for 4 months till the lower unit went out one day and the boat lost forward & reverse.
The lower unit was replaced and now I bought the boat and cant get it to start.
It will fire up soon as you hit the key but dies in about 2 sec.
If I stay at the engine while someone cranks it and play with the choke & hold the throttle about 1/2 way open it will start and run rough for about 20-30 sec. It appears to be flooding bad and a small amount gas does run out the opening of the caburators. When it does start and run for the 20 seconds it bogs bad and barely runs till it dies.
I thought the floats might be bad or adjusted wrong but they were new and set right. I ran a compression test today and all 3 cyl were EXACTLY 100psi.
Timing is perfect
compression is good
spark is good
carbs are SUPER clean & float is set right
fuel pressure is good
What am I missing?
What would make the carbs leak gas out of the venturis?
What could be making it run SOOO rich & flood out?
I am thinking now that the reed valves may be trashed. The engine was 33 years old and after the rebuild maybe the higher compression cracked or destroyed the reed valves, That would cause the poor running as very little fuel/air is getting into the engine & also with every down stroke of the piston instead of compressing the fuel / air mixture it would blow it partially back out the intake and carbs. Maybe? what do you think?
Any help would be appreciated
Mike
