repairing Lower end

[JJB]

I wanted to get some input on doing a check out of my lower end . Its a 2000 175 Johnson vxsss 25 " . I been getting a low grumbling noise at 600 to 1200 rpm thats when its the worse . Its been bugging the hell out of me so I paid a OB machanic to take a ride . He said he though the noise was coming from the lower end due to the vibrations we were getting also He notice it as we came off a plane and slowed down . . I did rebuild my force lower unit years ago and wanted to know how hard it is on Johnson 175 and what special tools are needed . I know the manual shows a slew of tools needed but what is really needed to do the Job . I just dont want to spend $1800 to $2500 if it's a repair I can do for $500 . any Ideas what to look for when I get it open with those type of problems ?

 

[HighTrim]

Re: repairing Lower end

I would check out the torque on the prop nut first, you may get lucky.

Any type of damage to the prop?

Are you positive it is coming from the lower unit, and not the cowl rattling, flywheel magnet come loose, etc... ?

Check the flywheel for play, up and down, back and forth. (Motor not running of course!!!!)

Does it go away when tilted up a bit?

Lastly, you seem to be at the RPM's where there is a transition phase from the low to mid range carb circuits, have you tried a link n sync? Do you have a manual?

 

[JJB]

Re: repairing Lower end

Hey High trim , I love to get lucky on this one ! I have had the carbs and link and timming check by myself and three other people every think check out good . The ss prop is tight and have also tried a second aluminum prop to rule out prop and is not as bad with the aluminum prop but still there . I have also check out the bolts on the bearing housing are tight . but yes the noise does reduce some if tilted up but still has vibes through the boat and still rumbles as you back down off the throttle from a plane . It seems to be getting worse the more I use it over the last few weeks , whats you thoughts on this one ? Thanks again for the input !

 

[HighTrim]

Re: repairing Lower end

I wonder if it is a harmonic iteraction at that RPM with something on the motor?

The decrease when running with the Aluminum prop may be a clue. Any play in the propshaft?

 

[JJB]

Re: repairing Lower end

Yes there is some play in the shaft ! There is more play in and out but there is some side to side also !

 

[flabum]

Re: repairing Lower end

How does the oil look? Does it have any signs of metal or water? Have you checked the propshaft for being bent?

 

[JJB]

Re: repairing Lower end

The shaft looks good when I spin it but I did have some metal shavings on the drain plug when I changes it two weeks ago

 

[flabum]

Re: repairing Lower end

How big are the flakes, and have you ever hit anything?

where in Fla are you?

 

[JJB]

Re: repairing Lower end

Hey flabum NO never hit anything , the flakes are small .I am in the ft lauderdale area

 

[flabum]

Re: repairing Lower end

Normally the flakes should look like peach fuzz on the magnet. If you are getting shavings longer than 1/16" then you probably have a bad bearing somewhere. Usually a bad bearing will make the gear lube look pearly as you drain it if the lube has 50 hours or more on it.

 

[JJB]

Re: repairing Lower end

High trim wonder if it is a harmonic iteraction at that RPM with something on the motor? My question is how do I find if it is harmonic iteraction ?? and how much shaft play is normal ?

 

[HighTrim]

Re: repairing Lower end

High trim wonder if it is a harmonic iteraction at that RPM with something on the motor? My question is how do I find if it is harmonic iteraction ?? and how much shaft play is normal ?

I wish I could answer that. I have a few rattles in my car at certain RPM's

Hopefully some of the guys with these newer motors can let you know how much play is normal on the prop shafts.

"http://www.crowleymarine.com/brp_parts/diagrams/37679.cfm"

 

[JJB]

Re: repairing Lower end

Thanks for the help high trim , I was Just checking the play again and it seems to be a lot of play up and down and side to side , I know there should be some in and out but the side to side does seem to be little excessive I think . Hope someone on here can give me a better Idea about it . There no water in the lower unit oil and just check again for metal on the plug and it clean .

 

[JJB]

Re: repairing Lower end

can you run your motor in gear on the garden hose with muffs to see if prop has odd movement in it ? I know keep the dog away !

 

[HighTrim]

Re: repairing Lower end

Keep the RPMs down under 1500, and not for long. The last thing you want is your outboard going into thermal runaway.

 

[iwombat]

Re: repairing Lower end

I think the last thing I'd want is to be attacked by a pack of rabid waresquirrels during the whole process.

But, I'd put thermal runaway right up there on the not good list.


Just Sayin'

 

[HighTrim]

Re: repairing Lower end

I think the last thing I'd want is to be attacked by a pack of rabid waresquirrels during the whole process.

But, I'd put thermal runaway right up there on the not good list.


Just Sayin'

tks for the afternoon chuckle
What kind of critters do you have up there in North Bend!