don't want to highjack the Autoprop thread

dohenyboy · #1 (**permalink**) 09-09-2008

but I have an Autoprop and I have a problem with it.
When I start out, I have my engine at idle and then put the transmission in forward. As I advance the throttle, the engine speed does not increase. I will eventually climb up to about 2 knots in speed, nothing more.
If I put the lever in neutral, the engine rpms increase normally.
If I have the rpms at about 1500 and slam into forward, the engine keeps the rpm and I can accelerate to displacement speed. which is okay but I think its hard on my gearbox.
Any ideas on what is happening?
thank you

artbyjody · #2 (**permalink**) 09-09-2008

Try giving it more "gas" after you have placed the control into forward or reverse for about 20 seconds or so. It will cause some cavitation but when you reduce the "gas" you'll be able to throttle and control the the speed appropriately.. depending on the pitch of your prop - will determine how much you need or how long you need to cavitate.. If it is still an issue then you will want to look at changing the prop pitch at some point (which I had to do with my feathering prop)...

Good luck

sailingdog · #3 (**permalink**) 09-09-2008

It actually sounds like your autoprop needs some maintenance. It isn't opening properly...sticking shut, so you don't get the speed out of it, unless you kick it open by switching from neutral to forward at 1500 rpm.

christyleigh · #4 (**permalink**) 09-09-2008

Quote:

Originally Posted by sailingdog

It actually sounds like your autoprop needs some maintenance. It isn't opening properly...sticking shut, so you don't get the speed out of it, unless you kick it open by switching from neutral to forward at 1500 rpm.

I think SD's first sentence covers it but I'll add a bit from having installed an AutoProp on my last boat for 5 years and another 3 years with the AutoProp that came on my current boat. AutoProps don't open and close. They are Featherers not Folders. The name "AutoProp" comes from the fact that they Auto Pitch themselves driven by the Need or Not by things like being helped by sails etc... If in fact your AutoProp was wrongly pitched to your hull/motor config you would have to send it to the factory for adjustment. If as you say when you properly - and Don't do it any other way - shift at an idle it won't spin up it sounds like in that particular case the blades were so stuck out of alignment that your engine couldn't handle it. They may need lubrication which is recommended at least every other year. While my boat is still tied to the dock I always kick it into reverse, rev it a bit, and then to forward to make sure it's doing what is should. If I don't move the whole floating dock system at least a few inches in each gear I know I have a problem

- but that has never happened in 8 years with AutoProps. Great for Motor-Sailing because it self adjusts/pitches to the needs of the engine

jrd22 · #5 (**permalink**) 09-09-2008

If I understand the OP correctly, the engine doesn't increase RPM at all when in gear. Sounds like something is fouled on the prop to me. You should be able to reach governed RPM with the Autoprop even when tied to the dock. Even if all the blades were stuck in the maximum pitch position (hard to imagine how this would happen) you should still be able to increase RPM, but the engine would probably be making black smoke and wouldn't reach full speed. I would have a diver check what's going on down there.

John

christyleigh · #6 (**permalink**) 09-09-2008

Quote:

Originally Posted by jrd22

If I understand the OP correctly, the engine doesn't increase RPM at all when in gear. Sounds like something is fouled on the prop to me. You should be able to reach governed RPM with the Autoprop even when tied to the dock. Even if all the blades were stuck in the maximum pitch position (hard to imagine how this would happen) you should still be able to increase RPM, but the engine would probably be making black smoke and wouldn't reach full speed. I would have a diver check what's going on down there.John

That was my first thought also but the OP said once he got it (jammed it) into gear he reached hull speed which is why my best Guess would be sticking.
By the way one other thing I didn't mention in my earlier post is that the AutoProp completely Reverses the Blades in Reverse. That is why they back up just as strong as they go forward - But that also means if they get stuck in the middle the thing has absolutely No Resemblance to a Prop and would offer Extreme Resistance to turning not just the "maximum pitch position" John mentions. But agreed..... the poor engine should be belching smoke and the prop shaft should be dancing a jig and sounding like it wants to free itself from the boat if it was stuck with the blades all facing different directions

dohenyboy · #7 (**permalink**) 09-09-2008

thank all, yes prop is clean, diver says all looks well. I have to haul it out to get the antifouling renewed so will plan on lubing it. don't think that has been done since I have had it (three years)

sailingdog · #8 (**permalink**) 09-09-2008

dohenyboy-

it may need to be shimmed or such, since lubrication isn't the only thing that can cause a folding/feathering prop to stick.

RXBOT · #9 (**permalink**) 09-09-2008

Isn't the Autoprop feathering not folding? But I assume it could get stuck in any position, such as stuck in reverse configuration when UR trying to go forward or stuck in feathered and you can't go anywhere. If the prop is not acting normally I can see severe potential problems. Poster should get it pulled and serviced by competent facility.

jrd22 · #10 (**permalink**) 09-09-2008

Rxbot- you're correct, it is a feathering prop, or variable pitch. Each blade is completely independant of the others. They rotate on individual bearings and just flop around when you turn the shaft slowly. They are built so that the centrifugal force throws them out in the correct direction, forward or reverse, and the higher the RPM the finer the pitch until the boat speed increases the water flow over the blades so they increase the pitch. You really need to use a lot of throttle initially to get going or stop (but you can stop on a dime if you need to). In a rough sea where forward speed is constantly changing the blades change with the speed, continuously and automatically, without changing the engine RPM.

I don't think that this could be a prop issue if it is clean and the blades move freely (I would guess the diver would have checked this?), but I'm stumped about what might be causing it. Could there be fish line or something in the cutlass bearing creating a severe drag?

PS, I love the idea of the Autoprop and it works great, just not sure I'm going to put one on the new boat in light of the reports of the newer ones losing blades.