Coupler, Prop or Cavitation ?

[starsnstripers]

Happy Turkey Day!!! Was wondering if anyone ever experienced this? !970 L-6 165hp MC-1 drive > I was cruising this afternoon off the coast of Maine returning from some Island hunting. Going along smoothly at 3000 rpm and all of a sudden something slipped or? the rpms reved and boat slowed down. I brought the throttle back and went slow for a bit. We thought we noticed a large chunk of seaweed come out from behind us. Dont know if it was stuck on prop or what. Tried to bring throttle up to plaining speed again and it did it again. So i puttered along till we got closer to the dock. Thaught we saw another chunk of seaweed pop out from the drive. Being close to the launch now, I tried the boat out again up to 3000 rpms 3 times and it was fine. from idle i gave her a good dose of throttle and it never slipped again. Do you thing a chunk of seaweed could get lodged around prop at that speed and cause cavitation? Or, Is the coupling letting go? Or maybe the prop bushing? When a prop bushing slips or a coupler slips wouldn't it continue to slip? Any comments or experiences would be appreciated.

 

[Don S]

Re: Coupler, Prop or Cavitation ?

A prop or coupler wouldn't heal. If they slip, they stay slipped and get worse.

Seaweed has caused worse problems.

 

[starsnstripers]

Re: Coupler, Prop or Cavitation ?

Thats what i was hoping to hear Don Thanks. We'll try her again tomorrow.

 

[Trent]

Re: Coupler, Prop or Cavitation ?

I agree with above. But to put your mind at ease try this. Use a marker and make a mark across the prop hub and go use it, if the mark moves then the prop has spun. If the coupler is starting to spin your engine temp will rise.

 

[starsnstripers]

Re: Coupler, Prop or Cavitation ?

After trying it near the dock today when i got in and it was fine i'm going to run it tomorrow and if it's going to spin out it will. then i'll know. I'll watch temp and make a mark before i leave though. I just find it hard to believe seaweed caugt the prop and caused cavitation at that speed. But, hope thats what it was. Thanks Trent

 

[Don S]

Re: Coupler, Prop or Cavitation ?

If the coupler is starting to spin your engine temp will rise.

Not if he slows the engine down where the boat will still go forward at slow speeds. At that point, the impeller is being operated. The only way you can get an overheat with a bad coupler is if the splines are gone. Then, no matter what the upper gears will not turn, or the vertical shaft that turns the pump.

 

[FreeBeeTony]

Re: Coupler, Prop or Cavitation ?

Have had the same thing happen many times in the bay............next time just put it into revares and it will clear the weeds.

 

[starsnstripers]

Re: Coupler, Prop or Cavitation ?

Yeah after the slip i dropped it back to about 1000 rpms and it wa fine. Gave it some throttle and slipped again, dropped throttle again. Puttered in to dock about a mile. Tried it out near the dock incase of a failer and it was fine got up on plane three times. Temp was fine too.

 

[starsnstripers]

Re: Coupler, Prop or Cavitation ?

Thanks Tony, there were some good seaweed floats out there today. Will see in the morning.

 

[mthieme]

Re: Coupler, Prop or Cavitation ?

The best way to clear seaweed (short of getting wet) is to go in reverse.

 

[dan t.]

Re: Coupler, Prop or Cavitation ?

had this happen lots of times, usually a small stick or a piece of kelp, a quick shot in reverse will usually clear it up.

 

[starsnstripers]

Re: Coupler, Prop or Cavitation ?

Thanks for the tips guys, I didnt get out today but going tomorrow. I should have lifted the outdrive the first time it did it to see if there was seaweed on it i guess. Oh well, we'll see tomorrow. Glad to know it's a common thing. I couldn't imagine that happening at that speed, Huh! I thought the worst.

 

[starsnstripers]

Re: Coupler, Prop or Cavitation ?

Update: Thanks people, It was infact Seaweed Did a 35 mile trip yesterday with out a hitch. I was a little nervous of something major there. Got two more trips this season and I'll put her away till spring. Had a great season thanks to all the help here. Happy Holidays!

 

[Don S]

Re: Coupler, Prop or Cavitation ?

Isn't it great when you expect the worst, and find out it was nothing.

 

[starsnstripers]

Re: Coupler, Prop or Cavitation ?

Absolutely Don! It doesn't happen often But when it does it's great. Running a 72 boat with a MC-1 drive and a 69 Motor on a shoestring budget, I'm relieved. Thanks