'57 18hp with a hickup.

[Hanr3]

I have a hick-up, the slower the rpm's the more pronounced it is, too slow it will kill the engine.

Little background
Replaced coils, condensers (.20), wires and plugs (.30).
Rebuilt carb, replaced cork float with a plastic one.
Was going to replace water pump, however it was in great shape. Can you put the water pump in backwards? As in the vanes are longer then the cavity and they must bend, does it matter which way they bend, clockwise, counterclockwise?

I adjusted the carb per the sticky, however my high speed needle valve is closed, and the low speed is 1/8 turn from closed. I can pull start it in one or two pulls every time. It'll idle fine, except for the hick-up, seems sluggish getting up to high speed, and the hick-up will settle down to a burb the higher the rpms.

Not sure if this matters, however the engine is sitting on my car engine stand and it leans forward, as opposed to sitting on the transome sitting vertical/backwards.

Just trying to list everything I've observed. Looking for some help.

Thanks!

 

[lindy46]

Re: '57 18hp with a hickup.

Your high speed needle can't be closed, or the motor wouldn't run. Must be cracked open some. And the low speed is too lean - causing the sneeze. Open it up a bit. Then get out on a lake and run the motor at WOT. Adjust the high speed to optimize speed. Then idle down to a troll and fine tune the low speed. Impeller vanes should be set with the tips curved away from the direction of rotation. Shaft rotates clockwise when viewed from above. With a new impeller, they will "right" themselves once you run the motor. However, with an old impeller (which I probably wouldn't have re-used), there is a "set" to the vanes, and it's probably best to re-install it with the same direction of rotation. Installing it backwards could result in failure of the vanes.

 

[BSDenning]

Re: '57 18hp with a hickup.

The waterpump impeller cannot be put in backwards. Either way you put it in, it should pump the same. I would go ahead and replace the impeller, just for the piece of mind of knowing that it is new and should be good for several years.

As for the hickup, it sounds like a carb issue to me. I don't think the correct setting of the high speed needle should be turned in all the way. There is a notch on the high speed knob that will stop it from turning all the way around, because it will come into contact with a metal bar that comes down from above the knob. You can take the metal bar off. I think it is attached by one screw. Then you may be able to turn the high speed knob further in. You can also remove the screw in the center of the knob. Then you can remove the whole knob and just turn the needle.

I'm just a novice, but I'm sure that someone with more experience than me should be able to help you out.

 

[Hanr3]

Re: '57 18hp with a hickup.

Your high speed needle can't be closed, or the motor wouldn't run. Must be cracked open some. And the low speed is too lean - causing the sneeze. Open it up a bit. Then get out on a lake and run the motor at WOT. Adjust the high speed to optimize speed. Then idle down to a troll and fine tune the low speed. Impeller vanes should be set with the tips curved away from the direction of rotation. Shaft rotates clockwise when viewed from above. With a new impeller, they will "right" themselves once you run the motor. However, with an old impeller (which I probably wouldn't have re-used), there is a "set" to the vanes, and it's probably best to re-install it with the same direction of rotation. Installing it backwards could result in failure of the vanes.

I'll replace the impeller and make the adjustments out on the lake. Kind of hard to do in my plastic garbage can, by time I get to WOT I dont have enough water left in teh can to cool the engine and I have to shut it down.

Is there an adjustment for the carb float?

 

[lindy46]

Re: '57 18hp with a hickup.

You can't adjust it properly in a barrel of water. In fact, you shouldn't be running at high speed in a barrel, only at idle or a little above idle. The carb float should be pretty close to parallel with the carb body. I usually bend it down just a little bit from parallel to assure it closes the needle without overflowing.

 

[Hanr3]

Re: '57 18hp with a hickup.

Thanks for the info.

Prior to reading your post, I adjusted the float to level, and now it can't get it to run, and it leaks gas out of the carb. After dinner Im going back out to readjust teh float back to where it was, put the needle valves where they were, again, get her to idle and take it to the lake this weekend.

Another question, there is a brass plate attached to teh bottom of the flywheel, it controls the butterfly via a roller and linkage, is there a specific setting for this, it appears to be adjustable? The reason I ask is there appears to be a worn line, which appears to be more visible then in past history.

 

[lindy46]

Re: '57 18hp with a hickup.

Thanks for the info.

Another question, there is a brass plate attached to teh bottom of the flywheel, it controls the butterfly via a roller and linkage, is there a specific setting for this, it appears to be adjustable? The reason I ask is there appears to be a worn line, which appears to be more visible then in past history.

There should be a line on that plate - when the roller hits the line, the throttle butterfly should just start opening. As you advance the throttle, the roller will ride up that plate and at WOT the butterfly should be wide open. Adjust the plate to make it so. May be two lines at WOT - can't remember for sure. Maybe someone else can confirm that. I know there are two lines on earlier 15hp models.