SOMETHING BROKE TODAY...Need help please

[GaJeff]

81 Citation 19ft, 120merc 4cyl. MC1 Outdrive.

Went for a ride today with a fellow boater in case I needed a tow... Well I did. Today was actually the farthest I've taken the boat. I was going at WOT about 30mph and all of a sudden I lost all power and the engine revved up to 4500 before I shut it down. I checked to make sure I didn't lose my prop and it was there so... What happened? I can put it in gear and to forward at idle but any more and the engine just speeds up. So it is going in gear but won't go any faster than idle. I thought my shaft at the gimbal bearing broke but my prop still spins.

I haven't had the chance to ever open a sterndrive up so I'm not familiar as to how they work. I'm a diesel mechanic so I can in fact do the repairs I've just never worked on boats before so this is all new to me. Any help is appreciated in advance.

Jeff

 

[bigdaddypt]

Re: SOMETHING BROKE TODAY...Need help please

I could be wrong, but it sounds like you spun your prop hub. Do you have another prop to try? When it's happened to me in the past, it reminded me of a slipping car transmission.

 

[ktbarrentine]

Re: SOMETHING BROKE TODAY...Need help please

Sounds like you either spun your prop hub, or blew your engine coupling (either the coupling itself, or the shaft splines). Did you notice any change in water temp after the "incident" A spun prop hub would still get you good impeller flow. Coupling problems would cause loss of water flow to the engine. I'm leaning towards a spun hub, since a coupling problem would probably leave you with no prop spin at all. You should mark the prop shaft and the prop, take it for a "spin" and see if the marks move. (and you need to do this test in the water... you cant do this at home on muffs...

 

[fishrdan]

Re: SOMETHING BROKE TODAY...Need help please

Sounds like a prop with a spun hub, holds at idle speed, but slips under power.

 

[GaJeff]

Re: SOMETHING BROKE TODAY...Need help please

Yes exactly like a slipping clutch... My temp stayed normal. When I got it home on muffs it was like nothing had happened, but there is also no load on the prop as well. When I take the prop nut off and remove the prop will I be able to tell or do I need to take more apart? Like I said I'm new to the sterndrive world so I'm not sure what to do besides remove the prop. What am I looking for? After removing the prop will it be obvious or the other end of the shaft? When you say mark it where am I marking it at?

Thanks for the quick replies

 

[ktbarrentine]

Re: SOMETHING BROKE TODAY...Need help please

It wont be necessarily obvious when you pull the prop, thats why you do the test before you pull the prop. You mark the end of the prop shaft and/or the prop nut/lockwasher tab with a permanent marker (something that wont wash off in the lake). Then put a corresponding mark on the prop near the prop nut (on the prop metal itself). Then you take it for a load run. Trailer it up (or take the boat out of the water) and see if the marks have moved relative to each other. Movement means the internal hub has spun. Make sense? good luck.

 

[GaJeff]

Re: SOMETHING BROKE TODAY...Need help please

If it were the main shaft at the gimbal would it be spinning around in the housing? Took the bellows loose for the main shaft and held on the the u-joints and tried spinning the prop in forward and reverse and it's locked in solid. Would the it need more force to spin the hub than what I could do or am I looking at another problem? I need to change the gimbal bearing and bellows anyways so I guess now is a good time to do it.

If I was getting good water flow to the engine and the prop seemed to be locked in with me holding the main shaft what else could cause this? I'm going to try the marking method sometime this week just want to know what all could cause this other than a spun hub or main shaft coupling.

Jeff

 

[ktbarrentine]

Re: SOMETHING BROKE TODAY...Need help please

You cant turn the prop by hand on a spun hub... you need to do this test in the water!!! We're not talking about the main shaft in the gimbal, we're talking about the prop on the prop shaft, by the symptoms you have provided. Either swap the prop, or do the match-marking method and take it for a run. Keep us posted.

 

[ktbarrentine]

Re: SOMETHING BROKE TODAY...Need help please

Took the bellows loose for the main shaft and held on the the u-joints and tried spinning the prop in forward and reverse and it's locked in solid.

I cant imagine why you would take the bellows loose to do this sort of test?!? Without removing the outdrive?!? now you have much more work in front of you putting that bellows back on correctly before you attempt another run in the water.:facepalm::facepalm::facepalm:

 

[GaJeff]

Re: SOMETHING BROKE TODAY...Need help please

The bellow had a crack in it and it's getting a new gimbal bearing and u-joints. The exhaust bellow also was split in several spots. My brother just bought this boat about a month ago and has no knowledge of mechanics at all. He done this without letting me check it out or anything. So I'm finding a lot of things that have been neglected and are probably all original. There was a small rip in the gimbal bearing bellow that has been letting water in for who knows how long and it started the growling when turning so before any more damage is done that has to be addressed. That is why it took it off to check. I figured the main shaft turns the gears for the lower unit and when it's in gear it all rotates. If I were to hold on to the main shaft and turn the prop with it in gear it would bind the main shaft and the prop would turn because of it being stripped out, but that's not what happened. It locked down and the prop did not move until it let go of the main shaft.

So before it goes back into the water I'm faced with a gimbal bearing replacement and all bellows. That's why I was asking if there was any other reason for these symptoms. I will remove the prop and check it out tomorrow and report back my findings. From the looks of everything it's all original so removing the prop alone my be a task. I was really hoping on marking the prop and going for a test run until I saw that crack in the bellow ..... Unfortunately it has to be done

 

[bigdaddypt]

Re: SOMETHING BROKE TODAY...Need help please

That sucks about the bellows and gimbal bearing, but yeah, get it done before it causes more damage. When that's done, do the prop test to see if it's spun. Best of luck.

 

[ktbarrentine]

Re: SOMETHING BROKE TODAY...Need help please

I figured the main shaft turns the gears for the lower unit and when it's in gear it all rotates.

Just a point of order....the main shaft turns the "gears" for the lower unit whether or not it is in gear. Putting it in gear just aligns the forward or reverse clutch dogs with the prop shaft in the lower unit to rotate the prop shaft/prop. (That's why the water pump in the lower unit is able to rotate all the time.) I think that is what you are trying to say, but you wouldn't believe the number of folks that didnt undertand the inner workings of the drive. And....it just doesn't work to try and hold the shaft still and try and turn the prop out of the water to check for a spun hub. It needs the load of being in the water. Best you can do know is put it on another boat to do the match-mark test. Sounds like you've got your hands full and the spun hub is the least of your worries for the time being.

Sorry to hear about all the extra work. best of luck and hope you can get 'er back up and in the water soon.

 

[GaJeff]

Re: SOMETHING BROKE TODAY...Need help please

Thanks for the advice... I know I probably sound like an idiot but it's just because like you said I don't know the inner workings of the drive yet. I can do semi truck engines, transmissions, and rears in the dark blind folded but an outdrive is "uncharted waters" for me...lol

Anyways planning on the gimbal bearing sometime this week and will inspect the rest of the drive while it's off. If I find something weird or out of place I'll let you guys know. Good thing summer seems all year long in south GA so I've got plenty of time to get it back in.

I swear it's one thing after another but I guess that what you get with a 30yr old boat

Jeff

 

[DaveG55]

Re: SOMETHING BROKE TODAY...Need help please

Just throwing this out there and hopefully someone with more knowledge than me can confirm or rebut this thought.
Since you will have the bellows and gimble bearing out I'd think that you may be able to see the engine coupler. If it has spun there may be bits of melted/torn rubber or some other "tell" that you could see. That is if a spun coupler is even still being considered.
I think the idea of putting your prop on another boat to test it is a good way to tell if yours has spun. I'd certainly do it for you one weekend as it's a very quick & easy thing to check. But I'm in middle GA (Lake Sinclair) so that may not be practicle for you.
Good Luck
Dave

 

[GaJeff]

Re: SOMETHING BROKE TODAY...Need help please

Thanks for the help.... If I can't find another boat to put it on I'll get in touch with you.

 

[dingdongs]

Re: SOMETHING BROKE TODAY...Need help please

remove cap off top of drive and see if your gears are still looking like a gear.you could put it in forward and see if all is well and the verticle shaft has not broke as it goes into the lower horizontal gear by rotating prop to see if engine rotates.try this before pulling drive.

 

[GaJeff]

Re: SOMETHING BROKE TODAY...Need help please

Would that also cause it to feel like a "clutch" is slipping or is it just an inspection?

 

[Don S]

Re: SOMETHING BROKE TODAY...Need help please

Would that also cause it to feel like a "clutch" is slipping or is it just an inspection?

NO.

Just mark the prop hub and prop and put the boat in the water an make it slip. Then pull the prop and see if the marks are still lined up. If they are lined up, you need a coupler. If they are out of alignment you need a prop repair or new prop.

 

[haulnazz15]

Re: SOMETHING BROKE TODAY...Need help please

remove cap off top of drive and see if your gears are still looking like a gear.you could put it in forward and see if all is well and the verticle shaft has not broke as it goes into the lower horizontal gear by rotating prop to see if engine rotates.try this before pulling drive.

I think I'd mark the prop hub before embarking down that road. If his gears are chewed up in the upper, he isn't likely going anywhere at idle, especially not without a ton of noise. The issue is 99% a spun hub or coupler given the info we have been given.

 

[GaJeff]

Re: SOMETHING BROKE TODAY...Need help please

Thanks for all the replies.... Based on the answers I've been given you guys are more than likely right (because I'm no boat expert by no means). Since I'm plagued with a gimbal job anyways, would it be ok to go forward with the match-marking test? From what happened the other day I think the current may take me away if I take it off the trailer. So I guess what I'm asking is if I just put it in the water and leave it in the trailer and put it in gear would that be enough load to check it? I could back off the trailer and run it back on. Don't want to back any further tha the dock because the current can be PRETTY STRONG at times and unfortunate the nearest lake is a few hours away.

Jeff