Loud noise from lower unit - UPDATE

[Scuda11]

Hi guys, out yesterday for a nice day at the beach with the family and decided to take the kids for a little run outside. Cruising along fine and all of a sudden hear a metal grinding type sound. Almost sounded like a got something wrapped in the prop. I slowed down to idle, it continued, so I shut it off. Then....it wouldn't restart. Would spin the flywheel only to a certain point, and then STOP. I could back off the flywheel a bit, but it would always stop after a few turns. So I am thinking a lower unit problem.<br /><br />Got a tow in (usually on the other side of that tow, 20 years in the USCG ) Then, luckily enough my uncle had his boat there, and towed me in later. When I got to his dock after about a 30 min ride alongside with my eng down, for craps and giggles I tried it again. This time it turned over, allot, in fact it almost started but didn't. I decided to leave it so as not to make anything worse.<br /><br />One thing to note. About 4 days I ago, I changed the lower unit oil. I didn't have the new oil flowing out of the top vent hole, but I could see it, and I was out of oil then (whole thing). I ran it about 3 times after that with no problems until of course yesterday. Oil was fine when I drained it, no metal flakes.<br /><br />So, should I get a lower unit lube oil pump and try to refill it and then start it, or pull it out of the water and inspect everything first? <br /><br />Of course, Murphy's Law, I just rebuilt the whole boat and now have engine problems, very frustrating!<br /><br />1983 200 hp Johnson pushing a 20ft CC Proline.<br /><br />Thanks in advance guys,

 

[R.Johnson]

Re: Loud noise from lower unit - UPDATE

You have a serious problem somewhere. You had no metal flakes the first time you drained it, or you have no flakes now? How much oil did you add before you ran out?

 

[Scuda11]

Re: Loud noise from lower unit - UPDATE

I havent check it for flakes this time, It is still at my uncles dock. I added almost the entire bottle/tube of oil.

 

[R.Johnson]

Re: Loud noise from lower unit - UPDATE

That gearcase holds 33 oz. of oil. This time you will probably find some flakes. Chunks more likely.

 

[Scuda11]

Re: Loud noise from lower unit - UPDATE

OMG, I am going to be quite ticked off at myself obviously. I will check it now, just curious, if I do find flakes, although I know that is bad, what exactly does it mean? A whole new lower unit, or can it be repaired? Thanks R. Johnson.

 

[Scuda11]

Re: Loud noise from lower unit - UPDATE

^

 

[Solittle]

Re: Loud noise from lower unit - UPDATE

It can be repaired but you may find it cheaper to buy a used (but OK) lower unit. It depends on what you find and what is available. Running it (if it will) without checking will most likely lead to further damage.

 

[Solittle]

Re: Loud noise from lower unit - UPDATE

It can be repaired but you may find it cheaper to buy a used (but OK) lower unit. It depends on what you find and what is available. Running it (if it will) without checking will most likely lead to further damage.

 

[Scuda11]

Re: Loud noise from lower unit - UPDATE

Thanks guys, I will check as soon as possible and post back.

 

[Scuda11]

Re: Loud noise from lower unit - UPDATE

Well, an update. I drained the lower unit oil and good news! No flakes of any kind, oil was a golden brownish. I replaced oil using my pump until it flowed out the vent hole. In the meantime I realized that I had in fact put in about 32 oz the first time, so just a little short.<br /><br />Then after a little coaxing, it started up! It was idling very high! However, after a couple of minutes, it stopped abruptly, actually the flywheel stopped abruptly if you know what I mean. When I tried to turn it over once more, it did exactly as it did in my first post, turned a little then the flywheel stuck. Does this still sound like a lower unit problem?<br /><br />Any ideas ?<br /><br />Thanks in advance

 

[Mark42]

Re: Loud noise from lower unit - UPDATE

Take out the spark plugs and have a look inside and at the plugs. Check for bits of metal on the plug, look for holes in the piston and scoring on the walls. If it's not looking promising, take the heads off for a good look.<br /><br />Could be jamming on broken ring or broken rod.<br /><br />Or it could be magnet come loose from flywheel and timing got advanced (high rpm) from things getting banged around by loose magnet.<br /><br />If its in neutral and the motor won't turn but the prop does, its a good bet there is a problem with the motor, not the lower unit.

 

[G DANE]

Re: Loud noise from lower unit - UPDATE

You will have to drop the lower unit to see if its powerhead or l/u, as pinion gear and forward and reverse gears spin all the time even in neutral, which only isolates propshaft from gears. Gear damage, which is what we are fearing, will most likely mean chuncks in oil. Marks guesses are good too, though, take compression numbers,check for magnet grinding.

 

[Scuda11]

Re: Loud noise from lower unit - UPDATE

Pulled out the plugs, I do actually see some metal flakes on the threads of the plugs.<br /><br />In neutral, prop will spin.<br /><br />There were no chunks in the lower unit oil.<br /><br />I noticed allot of black oil on the outside of the engine, underneath the powerhead if you will, that was not there before, also allot inside when I pulled off the cover.<br /><br />Looks like it may be time for a new engine doesn't it?

 

[Lasse Lehtonen]

Re: Loud noise from lower unit - UPDATE

I agree with Mark42. If there is a lowerunit problem the prop wont spin normally and the flywheel should be able to turn (motor should start) if gear in neutral. I would check the compression first, sounds like you have serious problem with your powerhead. After checking the compression you can decide what to do next - pull the head and look for a damage or to buy a new or used motor.

 

[G DANE]

Re: Loud noise from lower unit - UPDATE

In my opinion a little early to throw the towel yet.<br /><br />If suddenly lots of oil under hood, examine powerhead all around for cracks caused by a loose or broken rod. Especially everywhere around the crancks rotation radius.<br /><br />I do no agree that a free rotating prop tells anything of gears condition, only that rotates in neutral is propshaft and clutch dog. If no evedience of powerhead damage and fair compression, I would drop lower unit and try to start it with a hose on the coppertube up to power head. If signs of lower unit damage, open it up and see how bad it is.

 

[Mark42]

Re: Loud noise from lower unit - UPDATE

Might have eaten a crankshaft bearing and seal. That would account for irratic running and jamming, and oil leakage.<br /><br />I'm interested in what the source of this problem really is!