1960 40hp

[Bill Mattor]

Having problem getting my 1960 hp to top end.. With the throttle full out the engine is only a bit above idle.
If I shut it down and restart it picks up considerably but still does reach top end speeds.
Any thoughts out there?
Thanks, Bill

 

[F_R]

Re: 1960 40hp

Check to see if it's running on both cylinders. Have the coils been replaced? If not, they need to be. They are guaranteed to be dried up and cracked if they are originals.

A sheared flywheel key also comes to mind. Or badly screwed up throttle linkage.

 

[jimmbo]

Re: 1960 40hp

Is it getting enough fuel? Dirt in the carbs, badly misadjusted Hi speed needle can cause all sorts of problems. Is the fuel tank properly vented(i'm pretty sure the pressurized system had gone the way of the dodo bird by 1960), If it isn't the primer bulb usually collapes. perhaps the fuel pump is bad. As mentioned by F R, it could be ignition, even something simple like a bad sparkplug. A disconnected throttle linkage can prevent the carb from opening or the timing from advancing, or mess up the sychronization between the two. A plugged exhaust system can choke an engine. Mechanical problem might be the reason, scored cylinders/pistons, broken or worn piston rings.
There are 3 things an engine needs to run. Fuel, spark, and compression.

 

[BoatBuoy]

Re: 1960 40hp

I don't know your engine history, but I had one once upon a time that behaved very much like you've described. Turns out it was water in the float bowl. I removed the screw/plug at the bottom front of the float bowl to drain and tipped the engine up to assist draining. I replaced the screw/plug and it ran almost normal again.

 

[tashasdaddy]

Re: 1960 40hp

follow those post with this

http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=28;gtid=818798;gpid=818802

 

[58 Johnson]

Re: 1960 40hp

Has this one been resolved? When you have such a huge issue with power and speed I am wondering if the engine was, or is, even running on two cylinders?? All of the suggestions provided above are valid for sure whether the problem is that it is running on one cylinder or running on two, but poorly. If it's not running on two cylinders (feel the spark plugs after it has run a minute of two...are they both too hot to touch?), it could be due to many reasons.

As a for instance, I even had a Johnson 40 running on one cylinder once for which the marina insisted on doing the igntion all over when I told him it wasn't the ignition. Having paid my money and wasted it on their advice, I went on a search and found a screw had come out of one of the carburetor butterfiles and lodged in the reed plate keeping the reed open and the cylinder unable to fire.

 

[jimmbo]

Re: 1960 40hp

Lucky that it got caught and didn't make it into the crankcase. 1 carb feeding reeds for 2 cylinders won't necessarly spit/spray back fuel when a reed is broken, mising or comprised..

 

[58 Johnson]

Re: 1960 40hp

Yes, I was very lucky. The reed was stiff enough that the head of the screw wouldn't fit through. Like you said, there was no spit or spray back to see, but obviously there was not enough pressure on the downstroke to force the fuel to the combustion chamber. Interestingly, one sypmtom was lots of unburned fuel coming out of the exhaust (tiny white gas globules in the water)... there was not enough fuel in the combustion chamber to fire, so the unburned mix was heading right out into the lake.