Need some OMC help

[Singing Boat Guy]

Hi folks,

I just a bought an 18ft Sea Ray with an OMC 175 I/O and I need an impeller for the sterndrive. The model number of the sterndrive is 981059 and the serial number is W 962271. I am having trouble finding one here in Calgary and it would be extremely helpful is someone could point me to the right part number. How hard is this to change this part?

 

[HT32BSX115]

Re: Need some OMC help

Year model helps usually.

Go here and here

 

[Gary H NC]

Re: Need some OMC help

What year is the drive? Is it a Cobra?
All the Cobras use the same impeller kit.
Easy to change by removing the plastic housing on the back of the drive then the water pump cover.

Here is an example,
http://www.go2marine.com/product.do?no=82785F&WT.mc_id=gb1

 

[Singing Boat Guy]

Re: Need some OMC help

I am not sure if it is a cobra or not. All it says on the back is OMC 175 HP and the model and serial # are what I provided in the original post.

The guy I bought it from had never had an inboard before and ran water to the moter, but not the sterndrive and said that he burnt out the impeller. How does one run water to the sterndrive and how would I know if the impeller is burnt out of not? Also, could there have been anymore damage than that? When he started it for me you could see that the prop turned.

I am pretty new to boating and hope I didn't buy a mistake.

 

[Gary H NC]

Re: Need some OMC help

What color is the drive painted? Is there 2 hydraulic rams on the lower part of the drive that lifts it up and down?
Does the drive look like this?

 

[Singing Boat Guy]

Re: Need some OMC help

The boat is an 18 foot Sea Ray SRV 180 with a serial number of SERA 58860176 - 180745

Not sure of the year. I was told it was a 79.

 

[Gary H NC]

Re: Need some OMC help

Also all it takes is a minute of running the drive with no water to ruin the impeller.
You need a set of muffs that clamp to the drive in front of the prop over the water intakes.It hooks to a garden hose.About 6 bucks at Walmart..

 

[Gary H NC]

Re: Need some OMC help

If its a 79 then its not a Cobra. Cobras came out in 1986.
So i bet its a OMC Stringer drive.
The Cobra impeller is an easy fix.I have not changed one on a Stringer.Some of the other guys should chime in on this..

 

[Acer2428]

Re: Need some OMC help

What are the telltale signs of a bad impeller? This cools the outdrive I assume?

I ran mine for about 10-15 seconds to see if the motor would fire (dumb, I know).

 

[95yj]

Re: Need some OMC help

Impeller feeds water to the water pump on your motor as the engine water pump will not "prime" water from under your boat. The circulating pump (water pump on the motor) then runs this water through your engine and out the exhaust.

If the impeller is not in top shape, the engine might cool OK at higher RPMS but will overhead at idle and lower R's. Once it's shot, the engine will just overheat no matter what the R's

Running the motor with no water can totally ruin an impeller in about 45 seconds, less if the impeller is already degraded.

 

[Gary H NC]

Re: Need some OMC help

What are the telltale signs of a bad impeller? This cools the outdrive I assume?

I ran mine for about 10-15 seconds to see if the motor would fire (dumb, I know).

That short of time you are probably ok.
Sure signs of a bad impeller,engine overheat.
It may run cool hooked to a hose in the driveway but will overheat when the boats in the lake.
The impeller pumps water to the engine circulation pump on the engine...
If its over 2 years old it needs to be checked.

 

[Singing Boat Guy]

Re: Need some OMC help

My sterndrive is an OMC for sure. It does not have the water inlets in the sides behind the prop like my outboard did. It seems to be right above the prop under the Cavitation plate with a little metal grate covering it.

 

[Acer2428]

Re: Need some OMC help

Phew. Nope, she was fine on the lake idling and at speed.

Other than the sinking part

 

[Lyndy]

Re: Need some OMC help

If you do not have slits on the side of the drive for Muffs, and it is an OMC drive it would indicate the Drive may be 1977 or older. A picture or two from different angles may help narrow down the model year. Although a specific model year may not be needed for an Impeller Kit it will be somewhat important if anything else is needed when you attempt to replace the impeller.

 

[wire2]

Re: Need some OMC help

Your boat serial # ends in ...76, indicating the year of manufacture. The drive is likely the same, possibly + or - 1 year.

Impellers are made of stiff rubber and have radial "blades" spinning in a stainless housing. It's offset to create displacement, which makes it rub quite hard on one side. If it's dry, it will heat up and burn the blades off in less than 5 seconds. Personal experience, many years ago.

At this point, you can try it in a lake to see what happens.
If it doesn't cool properly you'll know by engine temp, at speed and/or idle.

If you have to replace it, it's not that hard. Remove the shift cable from the shift converter behind the engine, remove the outdrive from the boat, remove top cover and exhaust housing, remove upper gear housing, open water pump housing.

You may want to get a bolt-on flush adapter for future, more effective than muffs. Here's what to look for;
http://cgi.ebay.com/ebaymotors/Omc-...ryZ50442QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

 

[Lyndy]

Re: Need some OMC help

Just as an extra note, you probably have an electric shift so you will not find a shift converter nor a shift cable but a pair of electrical wires. It is also a better idea to get a complete kit that includes the impeller housing. Thumbs up on the flush adapter!

 

[wire2]

Re: Need some OMC help

Thanks Lyndy. You're right, most likely an electric. Probably easier to do.
I have my own '84 engraved on the brain. D'Oh!

 

[Singing Boat Guy]

Re: Need some OMC help

Does the sterndrive need to be removed from the boat to change the impeller?

 

[wire2]

Re: Need some OMC help

Does the sterndrive need to be removed from the boat to change the impeller?

I'm afraid so. My steps in post 15 above still apply, less the shift converter/cable part.

 

[Singing Boat Guy]

Re: Need some OMC help

Ok thanks, can I ask why the sterndrive must be removed? It looks as if I can just go right through the top of the drive.