Herman Melville
New member
Hi,
I have 1978 35hp Evinrude. model 358B62R to be precise.
Lovely engine - just bought it, giving it a good ole service over the winter.
I looked at the cam roller. when the throttle is almost closed at start idle it doesn't quite touch the CAM (16th of an inch)...when you open up the throttle there is a thin rod that comes from the plate moving mechanism where there throttle control comes into the engine. This rod opens and closes the throttle just like I expected the CAM roller to do but the CAM roller isn't really doing anything. As you move the throttle more and more open the cam roller is pushed further away from the cam - at ful throttle maybe 1/2 inch.
The rod is obviously OEM fitted and supposed to be there. You can adjust it's 'offset' to determine how much it opens or 'pushes' too. I guess it adjusrted to push a lot at the moment.
The previous owner reported it was hard to start - I suspect they tried to 'bodge' it to start by putting more gas and air in there by making that rod push further earlier and they have moved the 'stops' so that you can start the engine with the throttle butterfly wide open.
So I need to sort this - fine it will be very interesting.
But I am wondering - why have this push rod and the CAM roller to open the butterfly as the throttle is advanced - why not have just a roller or just the rod?. On my 1992 15horse there is just a CAM roller.
How do the two work together? If you wanted the CAM roller to open in a very specific way you could just have a different shaped CAM.....
I would like to know the background before I go messing with it.
I have 1978 35hp Evinrude. model 358B62R to be precise.
Lovely engine - just bought it, giving it a good ole service over the winter.
I looked at the cam roller. when the throttle is almost closed at start idle it doesn't quite touch the CAM (16th of an inch)...when you open up the throttle there is a thin rod that comes from the plate moving mechanism where there throttle control comes into the engine. This rod opens and closes the throttle just like I expected the CAM roller to do but the CAM roller isn't really doing anything. As you move the throttle more and more open the cam roller is pushed further away from the cam - at ful throttle maybe 1/2 inch.
The rod is obviously OEM fitted and supposed to be there. You can adjust it's 'offset' to determine how much it opens or 'pushes' too. I guess it adjusrted to push a lot at the moment.
The previous owner reported it was hard to start - I suspect they tried to 'bodge' it to start by putting more gas and air in there by making that rod push further earlier and they have moved the 'stops' so that you can start the engine with the throttle butterfly wide open.
So I need to sort this - fine it will be very interesting.
But I am wondering - why have this push rod and the CAM roller to open the butterfly as the throttle is advanced - why not have just a roller or just the rod?. On my 1992 15horse there is just a CAM roller.
How do the two work together? If you wanted the CAM roller to open in a very specific way you could just have a different shaped CAM.....
I would like to know the background before I go messing with it.
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