OMC Stern Drive Impeller removal

[Celtichawk]

I know what impeller kit I will need but how difficult is it to replace? Will the outdrive unit need to be completely removed both upper and lower or as easy as removing a cover and find it?

Any diagrams or instructions will be greatly appreciated. Would hate to splash boat and the find out I have bigger problems and overheat motor.

 

[76 Lund President ll]

Re: OMC Stern Drive Impeller removal

I split my drive with it still attached to the boat. I lowered the bottom half with a floor jack and laid on my back to get at the pump. I used the exploded view as a guide. I bought genuine OMC parts from Crowley Marine. The website has OMC exploded views of the drive.

 

[ddnewb]

Re: OMC Stern Drive Impeller removal

I know what impeller kit I will need but how difficult is it to replace? Will the outdrive unit need to be completely removed both upper and lower or as easy as removing a cover and find it?

Any diagrams or instructions will be greatly appreciated. Would hate to splash boat and the find out I have bigger problems and overheat motor.

Not sure what one you have, but on my OMC I/O there's 3 bolts for a cover(triangle shaped) and underneath that the impeller housing(another 3 bolts). Grease up the new liner and impeller and it should pop right in. Again, not sure if it's the same as mine. I made the mistake of not inspecting the old impeller before ordering the kit. The liner spun, blocking the ports half way, and permanently damaged the housing. Had to put in another order and wait for a new housing to come in before starting.

 

[southkogs]

Re: OMC Stern Drive Impeller removal

You've got the electric shift: IMHO, it's just a bunch easier to drop that whole drive off. Mine takes me about 10 to 15 minutes to get off by myself. You can do it just by dropping the lower unit, but you need to be VERY conscious of your shift wires 'cuz they run all the way up into the inboard from the lower unit.

The impeller is at the bottom of the upper gearcase of the sterndrive. You can see the exploded view on THIS site (same site I referenced in your other thread). You can work on it upside down leaving it on the boat, or yank the whole drive and use the work bench

 

[Celtichawk]

Re: OMC Stern Drive Impeller removal

Thanks everyone I will decide over the next few days my approach. The problem I gave though is my driveway is on a incline and trailer sits too low to park in driveway during this evolution. So either I do it on the street in front of my house remove drive and service on work bench or I leave it I'm storage lot and perform the work there only removing lower unit. While I'm in there I figured I just order the kit with pump housing and replace that. Recommend that or don't bother? Not sure when it's been done and considering the age of my boat I would rather do it and be safe then sorry later.

 

[Celtichawk]

Re: OMC Stern Drive Impeller removal

" Mine takes me about 10 to 15 minutes to get off by myself. You can do it just by dropping the lower unit, but you need to be VERY conscious of your shift wires 'cuz they run all the way up into the inboard from the lower unit. "

Southkog:

You mention shift wires if you only pull lower unit off but what happens when you drop entire drive do I disconnect shift wires at the inboard?

 

[Celtichawk]

Re: OMC Stern Drive Impeller removal

And all in all I prefer work done myself to not have to pay labor but around Southern California area what would it typically cost me to have a shop or mobile service perform the work any ideas or guesses?

 

[southkogs]

Re: OMC Stern Drive Impeller removal

You mention shift wires if you only pull lower unit off but what happens when you drop entire drive do I disconnect shift wires at the inboard?

The shift wire MUST disconnect if you take the entire drive off. On mine, that's two knife connectors on the port side of the engine block just ahead of the intermediate housing - two seconds to disconnect.

When you're just taking the lower unit off, you may have enough length in your shift wires to remove the lower and hold it several inches off to the side. Mine doesn't, but I've heard of a couple that do. So, you need to be conscious of those wires while you're moving the lower around. On mine, I would wind up disconnecting the wires (to be safe) and would probably wind up pulling them through the intermediate and having to feed 'em back through ... in the end, I might as well go ahead and pull the drive.

As I said, IMHO it's just easier to pull the whole drive on an electric shift. Other opinions may vary.

And all in all I prefer work done myself to not have to pay labor but around Southern California area what would it typically cost me to have a shop or mobile service perform the work any ideas or guesses?

No clue - humorously, I've only found one marine mechanic in our area who was even willing to take an OMC into his shop. Dude wound up breaking more than he fixed, so I brought her home and stumbled through it myself.

 

[Celtichawk]

Re: OMC Stern Drive Impeller removal

Thanks again Southkog I believe I will attempt this soon. Might as well remove entire drive like you said even though its a ***** for weight but that's what buddies are for. I have removed one before to replace a boot on another smaller vessel so shouldn't be hard.

Other then shift wire which I do remember from last removal do I need to mark the triangle looking gear adjuster that assists with lowering and raising drive? The part on port side that has four bolts in it to allow you to raise or lower manually if removed. Also ball gears do they need to be marked for correct position when I go to install?

Should drive be in full down position when I attempt removal or what is correct position for this?

 

[Celtichawk]

Re: OMC Stern Drive Impeller removal

Here is to one more serious question. Over the weekend when I did run the engine on garden hose water did happen to leak out of engine block petcock valves. After a few minutes messing with them I found that they were not turn to close, previous owners mechanic opened them I'm sure when they rebuilt motor.

Where can I buy these petcocks? Only need two since one on port side and one on starboard side. Also do I need to put anti-freeze in my engine or is the system setup for raw water coolant only?

In case those didn't realize its a early model 1972 GM350. Water only came out when I used garden hose so I'm lead to believe it didn't have any AF beforehand and don't believe it will need it.

If it does need AF in engine where would I fill it since no radiator which leads me to believe it doesn't. Sorry if dumb question I'm just trying to make sure.

 

[Celtichawk]

Re: OMC Stern Drive Impeller removal

Without removing the outdrive if I wanted to test that the impeller is good could I launch boat at dock and run it on raw water at dock and keep close eye on the temp gauge?

I would like to change it for sure but given that it could be bad but could be good thought maybe I could test it first without causing any harm in order to see.

Found a guy local who is mobile service and he said he would do work for $80 a hour at three hours total plus parts and highly recommended change the drive oils while in there.

Not bad cost but still thinkin of doing myself just goin to take longer.

 

[Celtichawk]

Re: OMC Stern Drive Impeller removal

Any suggestions for the above questions?

 

[southkogs]

Re: OMC Stern Drive Impeller removal

...do I need to mark the triangle looking gear adjuster that assists with lowering and raising drive? The part on port side that has four bolts in it to allow you to raise or lower manually if removed. Also ball gears do they need to be marked for correct position when I go to install?

Nope. I usually rock the drive back on the quadrant gear to help me get it down on the stand I made for it. Makes it a single person job. Generally, I get my boy to help me put it back on so I can leave the quadrant gear to be the last thing I put back on.

Ball gears don't really care how they meet up.

 

[southkogs]

Re: OMC Stern Drive Impeller removal

Here is to one more serious question. Over the weekend when I did run the engine on garden hose water did happen to leak out of engine block petcock valves. After a few minutes messing with them I found that they were not turn to close, previous owners mechanic opened them I'm sure when they rebuilt motor.

Where can I buy these petcocks? Only need two since one on port side and one on starboard side. Also do I need to put anti-freeze in my engine or is the system setup for raw water coolant only?

In case those didn't realize its a early model 1972 GM350. Water only came out when I used garden hose so I'm lead to believe it didn't have any AF beforehand and don't believe it will need it.

If it does need AF in engine where would I fill it since no radiator which leads me to believe it doesn't. Sorry if dumb question I'm just trying to make sure.

Shouldn't need Anti-Freeze: UNLESS you have a closed cooling system. I'm not familiar with those, but the tell tale is a radiator-esque tank up toward the front of the engine usually near the top. Most systems cool with raw lake/sea water - which is my guess at yours. No anti-freeze, just let water flow.

Check NAPA for those valves. They carry an OMC line.

 

[southkogs]

Re: OMC Stern Drive Impeller removal

Without removing the outdrive if I wanted to test that the impeller is good could I launch boat at dock and run it on raw water at dock and keep close eye on the temp gauge?

I would like to change it for sure but given that it could be bad but could be good thought maybe I could test it first without causing any harm in order to see.

Found a guy local who is mobile service and he said he would do work for $80 a hour at three hours total plus parts and highly recommended change the drive oils while in there.

Not bad cost but still thinkin of doing myself just goin to take longer.

You could test it at the local ramp, yes. But since it's not really known how old the impeller is, the best option is to change it. Can't tell ya' about the mechanic's price. I've gotten completely away from using those guys anymore.

 

[Celtichawk]

Re: OMC Stern Drive Impeller removal

Thanks everyone I found those valves petcocks at local Home Depot last night. Here's to the right size *Cheers*, as for anti-freeze didn't think so and no I don't have a radiator or fill tank so it's got to be cooled by raw water then.

Wish me luck Thursday I'm gonna launch at ramp $12 cost to test boat near shore that way if temp rises I can shut it down immediately. Normal operating temperature should be 120 or so right and nothin more? (GM350). Not that it will matter engine size but figured I add that.

I don't want to pay someone to do work I can so just gonna take time, heck one day I may have to do it on my own and might as well learn now.

 

[Celtichawk]

Re: OMC Stern Drive Impeller removal

Not to mention previous owner can't explain to me either why engine overheated in the first place. Now that engine has been rebuilt its only a logical guess impeller went bad causing not enough or none at all of raw water to cool motor. Suppose some kind of blockage in water lines too but I don't know. If riser exhaust hoses got so hot they melted or split on one side then rest assured impeller is shot? And if it has not been replaced yet then it's probably still that way.

I will pay close attention to my gauges as it does work and the moment it starts to climb beyond normal temperature again I will cut motor quick. Secure to trailer and proceed with impeller replacement. Plan to do it soon anyhow but want to test things out first.

 

[Celtichawk]

Re: OMC Stern Drive Impeller removal

Nope. I usually rock the drive back on the quadrant gear to help me get it down on the stand I made for it. Makes it a single person job. Generally, I get my boy to help me put it back on so I can leave the quadrant gear to be the last thing I put back on.

Ball gears don't really care how they meet up.

Quadrant gear?

 

[Howard Sterndrive]

Re: OMC Stern Drive Impeller removal

https://www.google.ca/search?safe=o...urce=og&sa=N&tab=wi&ei=yHwTUtrVAuTeyQHdwICABg

 

[southkogs]

Re: OMC Stern Drive Impeller removal

Operating temp should be 160?. If it holds at the ramp, that's okay - but the reality is out on the water at speed you could get a different result.

If everything holds at the ramp, then dunk it and drive it. If it holds at idle or just a little throttle then you can run it up some. Work you way up to 80% throttle and see what she does.

... but, I would change the impeller anyway