Carbs and Props

[High Tide]

I have two questions:<br /><br />One, should the flaps in my carbs be all the way open with my throttle pushed all the way down? They are not, but the boat runs good. <br /><br />Two, I have a strange problem with my prop not stopping when I put the shifter into neutral. It takes about half a second for the prop to stop. It only does this when I go from really fast to neutral. Trolling and going into neutral does not do this. I hear a slight pop or click sound, and the prop stops. The motor runs good, I think (Not sure if the carb flaps should be all the way open), but I want to make sure this isn't bad for the engine.<br /><br />I have greased the shifter mechanism that controls the rod that goes to the lower unit, so I'm thinking maybe it needed some lube. I just don't wanna screw my engine up.<br /><br />If you have advice, please write back!<br /><br />Thank you!

 

[rogerwa]

Re: Carbs and Props

I may be missing the boat on this one, but your prop should spin freely when in nuetral. If the boat is moving the force of the water over the blades will cause it to spin.. I would say this is absolutley normal..

 

[12Footer]

Re: Carbs and Props

Good news,High Tide!<br /><br />The flaps in your carb serve two purposes. The outter-most flap is the choke. It shuts off all the air,so the engine gets fuel only,and at a higher rate. It should be open.<br />The other flap (inner-most) is the throttle vane. It should be closed or close to closed at idle, and when given throttle, it will open accordingly. As far as adjusting,if it aint broke....<br />The prop spinning and the clicking sound are normal,when you go from high speed and pull <br />abruptly back to idle. It's caused by the water spinning the prop,as opposed to the prop pushing the water.<br />There are two screws on the lower part of the motor. One reads "vent", the other "FILL".<br />To check the lube in the lower unit, remove the "VENT" screw, and stick a pipecleaner in (as you would a dipstick in a car). It should be full to the top,and be green. If it is grey or brown, it has water in it.<br />When replacing the screw,make sure all the old gasket material are removed from around the hole,and from the screw. Use a new gasket each time. They are available at all marinas and boating stores,and are cheap.<br /> An impact driver might be required to remove the screw,and it should be impacted a bit when tightened.

 

[High Tide]

Re: Carbs and Props

Thanks for the reply, 12Footer, but something still doesn't seem right. What happens is I put it in neutral, and then for a second, there is still a force coming from the prop. Then, it sort of "pops", and the boat fees like it is truely in neutral. I know when I go from fast to stop by killing the motor, I get a "click, click" until I put the throttle in neutral, but this is different. <br /><br />I have adjusted the shift linkage, and this makes absolutely no difference. The only think I can think that I might have done is advance the "timing (?)" on the CDI box on the motor. I didn't do this on purpose, but the piece that connects everything had been stripped, so I bought a new one and put it on. It's electronic, so I don't know if that can have any effect. I'm not sure how much of the motor is electronic and how much is not. But this is all I have changed. <br /><br />Wait, I did have the prop off. Is there a possibility I put it on wrong? What if that prop nut isn't tight enough? The washer goes on the outside, right? <br /><br />These are the only things I can think of.

 

[High Tide]

Re: Carbs and Props

Just thought I'd add that it does it going from forward to stop and from reverse to stop, same sound and same conditions. I don't know if it's harming the lower unit, with the popping sound, but engine performance is normal and speed is normal (pretty fast). I haven't messed with anything except the CDI unit, the propeller (took it off and ran it in a tank), and I also cleaned the carbs. I'm having trouble putting one and one together to get two here.<br /><br />Thanks!

 

[SeaBear]

Re: Carbs and Props

Call me nosey but is there a god reason why you need to do crash stops? It isn't exactly healthy for the gearbox to be subjected to these forces repeatedly? What happens in a lot of gearboxes [I'm assuming you have an outboard] is the force of the cone clutch is increased with the load on the prop now if you shift from wot to neutral [again I assume you have a single lever control] is the cone clutch may not disengage until the rpm has dropped and the force on the prop has reduced and at that point if the boat is still moving forward then the clutch is probably being thrown out of mesh by the water force on the prop and hence the 'pop'? My view is that unless you have to do this then allow your revs to drop to near idle before shifting into neutral?<br /><br />Anyone else agree?

 

[High Tide]

Re: Carbs and Props

No, I definantly agree with you, I just wanted to make sure I wasn't going to screw something up if I just slowed down before engaging it into neutral. I don't do it often, but the couple of times I did it, I heard the noise, and got worried.<br /><br />Now that you mention RPM's, I did advance the idle speed a tiny bit, and I thought that maybe the increased RPM's would lead to a late "disengagement", or something along those lines. I'll drop that down a little bit and see if that has an effect. I'm thinking it will. And if it doesn't, I'm thinking I won't worry about this too much.<br /><br />Thanks for the reply, SeaBear.