Motor turning faster than prop.

[rockmaster1]

Yesterday after about 2 1/2 hours out in the ocean, as I was heading in I passed an entrance to a harbor and throttled down because it was a little choppy there. Then as I begin to throttle up again about halfway to full it seemed like tyhe boat was no moving as fast as it should, so I incresed the throttle a little more, same thing happened but the motor was louder this time. It seemed like a car with no transmission fulid, the motor was going faster than the boat. Well I throttled down and tried 2 more times but got the same results. When I throttled down the boat still moved and I was able to turn around and go back into the harbor I passed. The boat seemed to run fine till I tried to go fast. I came home and checked the gear oil and when I opened the top screw, the oil just started to flow out making me think it was full. I also took off the prop and inspected the inside of the prop, but it looked fine with no signs of wear on the inside prop or the spleen it slides onto. I noticed on my throttle there is a switch on the shift handle called the Neutral Lock Bar. I really don't know what this is used for and thought when I throttled down maybe I squeezed it along with the throttle and maybe something unknown to me happened to put in in a neutral like stage at that point of the throttle. Any info will be greatly helpfull.....

 

[magster65]

Re: Motor turning faster than prop.

Sounds like you spun the hub in your prop.

 

[akriverrat]

Re: Motor turning faster than prop.

volvo penta?

 

[rockmaster1]

Re: Motor turning faster than prop.

I forgot to add that I have a mercruiser 3.0 alpha 1. I looked at the prop and really didn't see any wear at all.

 

[The Marine Doctor]

Re: Motor turning faster than prop.

Take the Top cap of the drive and have a look. Might have spun the gears.<br /><br />If this is not the case...might be the prop...or you have spun the driveshaft at the engine. You will have to remove the drive to see this.<br /><br />TMD

 

[rockmaster1]

Re: Motor turning faster than prop.

I forgot to add that I have a mercruiser 3.0 alpha 1. I looked at the prop and really didn't see any wear at all on the inside. What dose a spun prop look like?

 

[elpaso]

Re: Motor turning faster than prop.

A spun prop can not be seen. There is a rubber<br />insert in hub. Pull prop take to any prop shop.<br />They can check in 5 minutes.<br />Hope that this is the problem. If prop is good<br />you have a big problem.

 

[flashback]

Re: Motor turning faster than prop.

rockmaster1, there are only 2 things I can think of that would cause the engine to "slip" 1 is the prop hub which you hope it is, and 2 is the coupler which is what you don't hope it is. In any case, put the drive in gear and try and turn the prop, if you can turn it, then have someone look at the back of the engine and tell you if the input shaft off the outdrive is turning, if it is, and the engine is not, then the coupler is shot.... if not. then you have stripped the hub in the prop...... did you have any smell of burning rubber? if so, then it is almost certain that the coupler is stripped.......

 

[rockmaster1]

Re: Motor turning faster than prop.

Just to be sure I put it in gear and it turned one way making little clicking noises and would not turn the other way. It did this in both foward and reverse. When it did turn it didn't seem like it was in gear as I felt no resistance, just the clicking noise. Where would the coupler be located ? Is it also know as: Engine Coupler

 

[f_inscreenname]

Re: Motor turning faster than prop.

I agree with "flashback". The coupler (Engine Coupler) is bolted to the flywheel on the motor (yes it means a motor pull to fix it). An easy way to check the prop (if you can’t borrow one for a test) is to mark the hub and prop with a line, run for a min, then check your marks. If they don't line up you have found your problem. For your sake I hope it’s the prop.

 

[rockmaster1]

Re: Motor turning faster than prop.

I borrowed a prop from a friend and went for a test run today. The prop I borrowed was not the same pitch as mine, it looked like it pitched down a little flater than mine. My props pitch stood more upright than the one I borrowed. During the test It did not do the samething as the last time, I got what seemed like full thrust and the motor was not turning faster than the boat. What I did notice was my boats top speed was 30mph, when the other props top speed was around 37 mph and it seemed like my rpms were up around 50 on the tach at full speed. I'm not to sure but i don't remember the rpms being that high. When the Engine Coupler wears out does it go all at once or maybe just a little at a time. I can understand the boat moving slower because of the pitch of the prop, but I'm not to sure about the rpms.

 

[flashback]

Re: Motor turning faster than prop.

rockmaster, I think you found your problem, the replacement prop was less pitch which means less speed at normal rpms. you stated that the boat ran good with the exception that you were going slower at a higher RPM. that's exactly what it should do with a prop of less pitch........get a new prop of the same as the original and your problems will be over....................