1973 25HP tuning

[Leastbay]

Trying to get this thing tuned. model 25302A. When I bought it last month it had a high idle. So far Ive rebuilt the carb and changed lower unit oil. I havent had a chance to tune the carb yet but I am confused by something in the manual. Under carb adjustments there is a section called "throttle cam follower adjustments". I understand what its talking about by lining up the follower between the 2 marks but how do I see if the throttle valve is closed at this point?? Also it looks like a tune up involves pulling the flywheel, should I consider doing this? I thought i read somewhere you could make adjustments with a feeler gauge to set the timing?? is this true?

 

[racerone]

Some testing should be done by you.-----If spark will jump a gap of 5/16" or more the timing will be right on the money.---Next you do a compression test.----If those are ok you look at fuel system problems / adjustments.

 

[Leastbay]

any thoughts on the cam follower? I think I understand that I put the roller between the 2 marks. I did this by turning the throttle grip. Then I adjust the flathead screw so the throttle is closed. Does the throttle plate stay closed from the idle position all the way to fast when not in gear? thats what it seems like is happening when I follow these instructions. Also what is the best way to test for this 5/16 spark gap

 

[racerone]

Throttle plate opens with the roller at those marks.-----In gear or nuetral does not change that in any way.--------2 pieces of wire stapled to a piece of plywood / cardboard.-----Put one end in the plug boot.---Clip other end to the block.------Set gap between wires to 5/16" or more.

 

[Leastbay]

adjusting the roller pretty much fixed everything and i was able to tune the carb, I am missing part #0314689 but Im trying to make one from a hangar which is not going well. Is it necessary to have this mixture adjustment while im running? Can I do without it if the motor is running well?

 

[F_R]

How the heck did you set the roller with that link missing? That number is the link that opens the carburetor. It absolutely is necessary. Go to the Antique Outboard Motor Club website and post a free want ad on their classified ads pages.
www.aomci.org

 

[Leastbay]

no, its the link that connects the lean/rich knob to the needle valve. So you can adjust it with the cowl on. Its $40 plus whatever for the retainers. Kinda high

 

[F_R]

Sorry, I obviously was looking at the wrong link. No problem if the rich/lean one is missing.

 

[oldboat1]

10hp motors of that vintage have a similar linkage assembly, I think -- not sure about the fit for your 25, but worth a try. Might try Ebay too.

 

[Leastbay]

Yeah. I can find them but with the retainers to hold it I'm looking at $60. One of the more expensive parts.

 

[oldboat1]

http://www.ebay.com/itm/Control-Kno...ash=item3f58ba087f:g:6RIAAOSwcBhWZ6pU&vxp=mtr

good luck. will probably find a way.

 

[hardwater fisherman]

Once properly set you should not need to adjust that, unless the carb has been taken apart for cleaning or service.

 

[AlTn]

one older mechanic worked at a local dock in the early 60's that rented fishing boats w/motors and it was their practice to remove that link for the rich lean setting...too many folks would start adjusting on it before they'd gone 20 ft...they did leave the knobs in place to placate them

 

[Mohawkmtrs]

I made one a couple of years ago out of a wire clothes hangar with "Z" bends at each end. You have to assemble everything before installing.

Take your time with the bends...took me about an hour.

 

[racerone]

If you make it with 2 pieces it will be easy to install.----Just join it up after each piece is installed.