Johnson 40hp 2005 link and idle adjustments

T

tphoyt

Lieutenant
Joined
Jun 10, 2010
Messages
1,264
The came roller should be readily available.
What’s your location?
E Bay and Amozon likely have them.
If your homemade cam roller dimensions are off likely everything else will be as well so book specs aren’t going to help. Jmo.
 
G

Gemat1973

Cadet
Joined
Aug 26, 2024
Messages
14
tphoyt said:
The came roller should be readily available.
What’s your location?
E Bay and Amozon likely have them.
If your homemade cam roller dimensions are off likely everything else will be as well so book specs aren’t going to help. Jmo.
Click to expand...
I live on a Greek island. Every boat part shop here suggests I buy a different brand engine.... Anything except Selva.
 
R

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,829
Your motor is an elegantly simple machine.----Shops are only in business to MAKE MONEY.----Many do not care to help out a customer to improve their reputation.
 
G

Gemat1973

Cadet
Joined
Aug 26, 2024
Messages
14
racerone said:
Your motor is an elegantly simple machine.----Shops are only in business to MAKE MONEY.----Many do not care to help out a customer to improve their reputation.
Click to expand...
About the needle I can assume that some previous mechanic changed it from another engine and I can accept that it works at 5,5 turns instead of 2,5.

The thing that buffles me is the suggested idle position of the roller in conjunction to the position of the idle screw that is supposed to be 1/2 inch. This is not mechanically possible. Only if a part like the throttle plate or the spark lever is not the original one ......

Well I have spend countless hours reading and working on this engine to make it run as it should. I feel I have it at a good point even if some settings seem to vary from the manual. I am going to try the boat at sea.
If it runs as good as it does with the muffs and performs well in all the power range I am not going to mess with it any more....
 
S

saltchuckmatt

Commander
Joined
Jul 19, 2019
Messages
2,647
Perhaps the needles where screwed in to far and they were flattened.

Not sure if you can see this but there are other adjustments. Did you loosen the screw on the carb just below the idle circuit?

0 new items by Matt Paulsen

photos.app.goo.gl photos.app.goo.gl
 
G

Gemat1973

Cadet
Joined
Aug 26, 2024
Messages
14
saltchuckmatt said:
Perhaps the needles where screwed in to far and they were flattened.

Not sure if you can see this but there are other adjustments. Did you loosen the screw on the carb just below the idle circuit?

0 new items by Matt Paulsen

photos.app.goo.gl photos.app.goo.gl
Click to expand...
Yes, I readjusted all that according to the service manual. Now when idle there is no pressure to the carb roller and both carb horns are snap closed. They move in sync when I open the throttle...
 
R

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,829
Facts-----The timing does not go out of adjustment on these motors.-----Except for a sheared flywheel key.-----Carburetion rarely goes out of adjustment on these motors.-----Owners often use the " lets see what happens if I adjust this linkage " -----They just proceed to make things worse.------Folks rarely trouble shoot to find the real issue !
 
S

saltchuckmatt

Commander
Joined
Jul 19, 2019
Messages
2,647
Have you pulled the flywheel? If so besides looking at the key you could see if the plate is not moving back all the way.

More pictures of all sides of the motor might help to see why this is not working per factory specs.
 
G

Gemat1973

Cadet
Joined
Aug 26, 2024
Messages
14
saltchuckmatt said:
Have you pulled the flywheel? If so besides looking at the key you could see if the plate is not moving back all the way.

More pictures of all sides of the motor might help to see why this is not working per factory specs.
Click to expand...
No, there was the original orange glue on the top nut so I didnt touch it.....
 
S

saltchuckmatt

Commander
Joined
Jul 19, 2019
Messages
2,647
Remove the nut then you will need a puller. I use an old steering wheel puller and three 1/4 inch screws. Don't be afraid to hit the top of the puller to get it to release.
 
T

tphoyt

Lieutenant
Joined
Jun 10, 2010
Messages
1,264
A Greek island sound nice.
I live on an island as well and I’m aware of the of the challenges of sourcing supplies.
My little patch of Paradise is over run with 200,000 tourists at the moment and it’s not so nice.
Agreed on getting the boat in the water to see how it really performs. That will tell you a lot.
All the Best
 
G

Gemat1973

Cadet
Joined
Aug 26, 2024
Messages
14
Gemat1973 said:
About the needle I can assume that some previous mechanic changed it from another engine and I can accept that it works at 5,5 turns instead of 2,5.

The thing that buffles me is the suggested idle position of the roller in conjunction to the position of the idle screw that is supposed to be 1/2 inch. This is not mechanically possible. Only if a part like the throttle plate or the spark lever is not the original one ......

Well I have spend countless hours reading and working on this engine to make it run as it should. I feel I have it at a good point even if some settings seem to vary from the manual. I am going to try the boat at sea.
If it runs as good as it does with the muffs and performs well in all the power range I am not going to mess with it any more....
Click to expand...
Update.
After some time messing with several things around the carbs and the linkages I managed to make the engine running as good as I could.
To make it idle right both idle screws have to be about 5 turns from fully screwed and the idle spark screw has to be about 3/4 of an inch instead of 1/2 that the manual says.
It idles at about 800 rpm, sounds nice and steady.
The boat planes at about 3/4 of WOT and then I can dial it down to 60% and maintain the speed of about 22knots. At WOT the rpm goes to just over 5500 rpm and the boat at just shy of 30 knots.
It sounds healthy and I will not further bother to replicate the manual's default settings. Clearly they do not apply to my engine maybe because the previous owner swapped a part of something that I cannot detect or because it is old....
 
You must log in or register to reply here.
Top