2gm20f Trans issue

[bcollis]

This is the second time it's happened, so I guess it's not a fluke.

Before I untie, I always put the boat in forward and reverse to be sure everything works as it should. I don't rev past 1200. So then we pull away from the dock, and run the engine for 15 or 20 minutes as we get out of the harbor, and I get the sails up. I always put it in reverse while sailing to avoid having it freewheel.

At the end of the session, I start the engine and put it in forward to keep us into the wind to drop the main, but the prop won't engage. It feels like I'm in forward, and I can hear the slight clunk of it going into forward, but the prop won't spin. I've figured out that if I rev up to around 1500, it will sometimes clunk, and then the prop spins. Reverse seems to be ok.

Once I get close to the dock, I test out reverse and forward, and it works like it should.

Trans fluid wasn't changed this year, the marina manager said the fluid looked new, and this is the first summer with the boat. I've put around 15 hours on the engine so far with no problems at all.

Could this be an intermittent cabling issue?

Thanks,

Brian

 

[higgs]

What do you have for a prop?

 

[zeehag]

my yannie dealer/distibutor guy sed to let the prop freewheel with boat in neutral while i sail my ericson with a yannie 2 qm 20 h. i never have any problem with my yannie. ever. or its trannie.

 

[bcollis]

It's the standard two blade. Should be clean, the boats only been in for a month.

 

[Benny17441]

You better go diving. It sounds as if you could have sheared the key that syncronizes the propellr to the shaft. The propeller goes into the shaft at very close tolerances and the adhesion by itself could turn the prop even without the key but when you are sailing with the transmission in reverse the water is pushing back with such force that could push the propeller back in the shaft breaking that friction hold. When you shift to forward now the thrust is pushing the propeller forward to where it could gradually regain adhesion. To test it, I would place it in reverse on the dock and this time rev the engine to maximum RPM and let it churn for a few minutes to see if you can replicate the ocurrence. In either case I would remove the prop and inspect the hub, replace the key and tighten the nut. Also inspect the shaft for any undue wear. If all checks out OK then it would be time to start looking at the tranny clutches. Good luck

 

[Stu Jackson]

Benny's got good advice. Also check the throw and cable at the transmission adjustment point at the engine. Good luck. Regardless of what the yard said, check the transmission fluid level yourself. You should know how to do that anyway, right?.

 

[bcollis]

Ouch. I was hoping for a simple cable adjustment, but after reading Benny' post, and now seeing Stu's, and looking over the Yanmar directive on freewheeling in neutral, I'm wondering what I may have walked into. Looks like I'll be getting wet next weekend, as well as dongle checking the tranny fluid.

Thanks for your guidance!

Brian

 

[bcollis]

Dongle checking = double checking.... Gotta love the Iphone...

B

 

[kloudie1]

Definitely check the cable adjustment first. Take the cable end loose from the lever at the transmission and shift it by hand.. if it engages correctly, adjust the cable to insure that it is going fully to forward and clicking into the detent.. .. Easiest stuff first.. then if that does not address the problem proceed to prop, coupling, etc..

 

[DougM]

I used to put my transmission in reverse beause I was taught not to let the prop freewheel. With the Yanmar, i was having a devil of a time re-engaging neutral for an engine start after sailing. After reading all the threads about not putting the transmission in gear, I thought I had betterfigure out another solution. Bought a folding prop. Expensive, but it works.

In reality, it sound as though your issure might be resolved by adjusting the shifter cable.

 

[fireman416]

Definitely check the cable adjustment first. Take the cable end loose from the lever at the transmission and shift it by hand.. if it engages correctly, adjust the cable to insure that it is going fully to forward and clicking into the detent.. .. Easiest stuff first.. then if that does not address the problem proceed to prop, coupling, etc..

I would definitely do as Kloudie says. I am a bit of a gear head and part of my mantra is to look at the symptoms and what may cause them, and then proceed to the difficult if nothing obvious is found. Often the fix is easier than you think and can be way less complicated if you look at the problem from a different prospective. Check your linkages and cables first.​

 

[tkanzler]

Next time you do your standard routine, and you don't think the prop is engaged in forward, have someone take the wheel and go below and look at the shaft. If it's turning with the engine (vary the engine speed and see if the shaft speed keeps up), then as suggested you may have sheared the prop key.

If it's not turning with the engine, then it's obviously not in gear, and cable adjustment is the first thing to check. Maybe not the last, if that's not the problem, but certainly the first. Could also be a sheared coupler key, so do look at all the parts to see if they all turn together, at the same speed, under all conditions of operation.

By the way, Bennie's advice is interesting (to me), as I've never seen a prop key sheared, but what he says makes sense.

 

[Scott]

neutral

Before doing anything, why not try sailing with transmission in neutral as directed by Yanmar. You may not have to do anything else.

 

[Witzend]

You better go diving. It sounds as if you could have sheared the key that syncronizes the propellr to the shaft. The propeller goes into the shaft at very close tolerances and the adhesion by itself could turn the prop even without the key but when you are sailing with the transmission in reverse the water is pushing back with such force that could push the propeller back in the shaft breaking that friction hold. When you shift to forward now the thrust is pushing the propeller forward to where it could gradually regain adhesion. To test it, I would place it in reverse on the dock and this time rev the engine to maximum RPM and let it churn for a few minutes to see if you can replicate the ocurrence. In either case I would remove the prop and inspect the hub, replace the key and tighten the nut. Also inspect the shaft for any undue wear. If all checks out OK then it would be time to start looking at the tranny clutches. Good luck

Seems like if it were sheered, than an rather abrupt event would have occurred. If this was not the case than more likely that the key is missing, if the shaft is indeed spinning.