lower unit problems

[Jeremy78]

I have a 1979 200hp mercury out board that I have been working for some time. The motor runs like new, when I engage the prop to go forward out of the water it opperates just fine. Motor goes into forward and reverse just fine. I recently took the boat to the lake for my first time out on the water since i bought it. Got the motor started and warmed up and tried to take off and she died when i tried to go forward. I got the motor running again and the same happened again, the motor died again. I pulled the boat out of the water and took it home. I started the motor up at home and it is clicking now when i put it into both gears before it goes into gear. I shut off the motor and tried to turn the prop with the motor in gear and it sounds like I have some type of rubber binding and rubber grinding. I replaced the lower unit oil yesterday and it looked like fine shavings at the tail end of the oil. A little discolored oil came out, nothing bad. oil looked good. The owner had the lower unit replaced before i bought the boat, so he said. Is the lower unit in need of a rebuild or is there something I can do to free up the lower unit so it will not bind and move easier. I am puzzled why it moves and opperater fine out of water but stalls and dies in water. Help would be nice

 

[Texasmark]

Re: lower unit problems

When you said MILK you just opened a can of worms. Water in oil turns milky; the yellower the milk, the worse the contamination. Water in lower units (or engines) corrodes gears and bearings. The longer it is allowed to stay there, the more severe the damage.

Working out of the water places absolutely no load on the gearing. In the water it is quite a different thing and problems will definitely show their colors.

Sorry to say sir, but apparently whomever redid the lower unit initially, did not find the problem that caused the initial problem.

Mark

 

[Jeremy78]

Re: lower unit problems

It was not the color of milk. The oil that they had nin there was dark<, and the tail end of the oil was starting to turn grey. I did not think it was water, but more like fine shavings. I should have said that in stead of milky, i will change that on the post. There was no signs of water in the oil

 

[Jeremy78]

Re: lower unit problems

would anything else besides the lower unit cause that much friction and kill the motor when i put it in gear. I am going to take
.the lower unit off what are some of the things i can look for that might have damage

 

[Texasmark]

Re: lower unit problems

Your idle could be set too low. Pull the plugs and put the engine in gear, reverse is preferred as it locks in both directions whereas forward locks in the thrust direction and spins in the reverse direction; but that will work, just gives you one direction for reference.

Grasp the prop with your gloved hand to prevent any possible injury from a sharp prop and see if you can rotate the prop in both directions with a fair amount of muscle.....muscle that an average 15 year old boy could muster sort of thing.

If you can somewhat easily do what I said, forget the LU and up your idle. There will always be "some" metallic shavings in the lower unit....nature of the beast.....that is why you change oil...to get rid of them periodically.

HTH,

Mark

 

[Jeremy78]

Re: lower unit problems

thanks for you imput, you are of the right track. The lower unit on my 1979 200hp merc. was really easy to take off, looked on youtube an they wallked me through it. To my suprise there was a rebuild tag buy the gear shifter. Long story short the man i got the boat from was honest( rare to find these days about a boat) and the rebuild was done right before i got the boat. I talked to the people that did the rebuild and they said that there paperwork showed that the only thing reused was the the housing. I change the plugs out again and took the throttle up a little. I am still getting a little clicking, like it is trying to go into gear but not getting full extension from the shifter cable to do so. When it is in gear the clicking goes away. I took the cable off out on the water and shiffted it by hand and it still grinded a little but it didnt stall out. I went about 50 feet and the motor died. I should have let the old motor warm up but i was excited that it worked and wanted to go for a ride. To my luck the batery went dead and that was the end of my trip to the lake. Is it normal for those old lower units to click a couple of times before it goes into gear?

 

[Jeremy78]

Re: lower unit problems

thanks for you imput, you are of the right track. The lower unit on my 1979 200hp merc. was really easy to take off, looked on youtube an they wallked me through it. To my suprise there was a rebuild tag buy the gear shifter. Long story short the man i got the boat from was honest( rare to find these days about a boat) and the rebuild was done right before i got the boat. I talked to the people that did the rebuild and they said that there paperwork showed that the only thing reused was the the housing. I change the plugs out again and took the throttle up a little. I am still getting a little clicking, like it is trying to go into gear but not getting full extension from the shifter cable to do so. When it is in gear the clicking goes away. I took the cable off out on the water and shiffted it by hand and it still grinded a little but it didnt stall out. I went about 50 feet and the motor died. I should have let the old motor warm up but i was excited that it worked and wanted to go for a ride. To my luck the batery went dead and that was the end of my trip to the lake. Is it normal for those old lower units to click a couple of times before it goes into gear?

 

[Texasmark]

Re: lower unit problems

They can and do. On my current 90 hp I run a XL 26P SS prop. A lot of pitch and a heavy prop. I only have a 3 cylinder engine which isn't real smooth at idle with this prop. At idle, moving forward in the water it is quite noisy but I understand what is happening and I am ok with it. If I have a ways to go, like from the wake buoys to the ramp, I just up the rpm's slightly and it quiets down.....the engine pulses to the prop are steadier and the prop doesn't get hammered intermittently so, with steady drive, the gear load is constant and no noise. If I take this prop off and put my 21P or any of my other lesser props on, there are no noises but I like the first one as I get dazzling performance out of it and that is the main reason I go to the lake now-a-days. Besides, lower unit gears are highly heat treated and tough as nails...don't believe it, try to machine one without removing the temper first. BTDT

Glad you are moving forward on this.

Mark

 

[BatDaddy1887]

Re: lower unit problems

You may need to do a link & sync according to your manual and it must be done in the steps given.

 

[Jeremy78]

Re: lower unit problems

I have been waiting for my manual to come in from ebay, so i am not familar with the link and sync.

 

[Jeremy78]

Re: lower unit problems

OK, i have the batery charged, muffs on and the motor is warm. Batery is and was not dead, it was the starter relay. it is going out so getting the motor was a little hard. The noise that I hear is like a clutch that is not fully ingaged. I know this might be a silly question, but is there a clutch. I have heard of something people call clutch dogs. Could this be what is not fully ingaged. the loud rubber grinding noise I heard was the water pump. I used a little marine grease inside the pump and the rubber grinding noise is gone. All noises are gone on the whole motor but that the grinding noise that i hear. The noise sounds like it is coming from the housing that is about the lower unit and not the lower unit it's self.

 

[Jeremy78]

Re: lower unit problems

I found the clutch dogg, how does this part work