800 stringer impeller replacement

[71wahoo]

I have a 5.7 omc with an 800 stringer outdrive. My boat overheats while at idle but once I reach 2500 rpm or higher the temperature drops to 140 - 160. I am assuming that the impeller is bad as the boat has sat for 3 years from the previous owner and he couldnt recall when he had it changed last. Now on to my issue with the impeller. I hear that the drive assembly must be removed in order to get to the impeller housing. Does anyone know where I might be able to get a schematic of how this is done? I have had three shops tell me it would be anywhere between 300 & 500 for them to replace. I am mechanically inclined and feel that this is a little steep for the impeller replacement so I want to tackle this myself. I thank everyone for their help in advance.

 

[Cuyose]

Re: 800 stringer impeller replacement

I have done it before, its kind of a pain as you need to remove the drive and separate the upper from the lower to get to the housing. Unfortunately I don't have an actual schematic available, although I would recommend ordering a shop manual if you are considering stuff like this.

Its not technically challenging and if you know your way around tools and engines it can be done fairly easily provided you don't find anything else wrong. There are definitely some precautions to take before you start this, shift cables etc. So make sure you got all that covered before you begin. Frankly if you got a quote of $300 to do it and you are not really hurting to save that money it sounds like a good deal to have it done.

 

[floattest]

Re: 800 stringer impeller replacement

this is how I did it in the link below

Getting the bolts out of the pump housing was the hardest part. They are in there with permatex on them and they were a BEEETCH.

you need to turn the blades a certain way when you put them in the housing. You need a manual if you don't have one.

I ended up replacing manifolds and thermostat and gaskets and the heat exchanger cap too. No it stays steady temp all the time.

hope you don't have to go through all that.


http://forums.iboats.com/showthread.php?t=323034

 

[71wahoo]

Re: 800 stringer impeller replacement

Thanks for the helpful info. I will definately be purchasing a manual and hope to have good news soon. Thanks again and happy boating!

 

[ekmanspiral]

Re: 800 stringer impeller replacement

I just took my outdrive off and disassembled it last weekend. I'm waiting for the impeller kit in the mail. I've never done any work on an outdrive before but lots on cars and motorcycles. Its not that hard. I did have to use heat and an impact wrench on the previously mentioned bolts. The shifter cables mounted on the bell housing were somewhat detailed but overall take your time and follow the manual and you'll be fine. I'm using the manual that is linked to in the sticky section. The pics are a little hard to see but its free.
good luck.

Oh ya, build yourself a stand out of 2x4's.
Neil

 

[wvwarlock]

Re: 800 stringer impeller replacement

here is the link to download the manual...

http://www.4shared.com/file/102988421/c4f26d54/OMC_64-86.html

this is a fairly simple job if you have mechanical abilities. should take you around 2 to 3 hours following the step by step information in this manual. i have the same manual and dis a complete upper rebuild and it is easy to follow and has diagrams and everything you need to complete the job.

Best of luck

 

[superbenk]

Re: 800 stringer impeller replacement

Get the manual for sure. You'll want that for a lot of other stuff too. Here's some pics of what it looks like inside when you're doing the job:

http://picasaweb.google.com/superbenk/ImpellerReplacement

As said previously, it's not a technically difficult job, just a bit of work. Get the manual & have the sealants on hand that it suggests using as well as your impeller kit.

Here's a diagram, but get the manual:

 

[full stringer]

Re: 800 stringer impeller replacement

its not the impeller

 

[studdy05]

Re: 800 stringer impeller replacement

Once you read the manual you'll see it aggitates to move water at idle whereas it pumps water via vacuum at higher rpms. It's possible it's the housing the impeller sits in, in other words. I always get the entire kit which containes the housing when I rebuild my sea water pump.

I've had your symptoms before, and rebuilding the sea water pump fixed it. And don't forget to shoot some grease in your swivel housing while your doing it. Those seals are part of the vacuum needed to get water to the pump and keeps exhaust gasses out.

Search the threads on here for an unorthodox way to change the pump out without disconnecting the drive. I'm not recommending it to a novice but I've done it in a pinch.

 

[dan t.]

Re: 800 stringer impeller replacement

vacuume pumping water at hi rpms ? wow some new laws of phisics here

 

[71wahoo]

Re: 800 stringer impeller replacement

Thanks for all the helpful info. I was told my symptoms are reverse of a what typically occurs when the impeller goes bad. I was told to look into the water pump and thermostat instead. I just looked up prices on this site and found that I can get the impeller kit, thermo. kit, and water pump for 165 delivered. I might as well replace it all being I have no knowledge of when these were last replaced. BTW I downloaded the free manual! That was a nice suprise.

Mike

 

[Howard Sterndrive]

Re: 800 stringer impeller replacement

shoot some grease in your swivel housing

and go enjoy the boat

I was told my symptoms are reverse of a what typically occurs when the impeller goes bad.

won't hurt to change the impeller, but your problem is probably the water pump sucking exhaust gases because it has never been greased

 

[run2car]

Re: 800 stringer impeller replacement

Had the same problem with mine, 78 5.0 Chevy OMC. Changed the impeller and housing and cured the problem.

 

[cr2k]

Re: 800 stringer impeller replacement

Pull the small bolts on the top cap and drop the drive and move to port side out of the way and lay on your back and pull the pump and housing. saves about 2 hours and a lot of headaches. Then you can bill for the full 3 hours. (oops, that was a tech secret, sorry)

 

[orchie18]

Re: 800 stringer impeller replacement

If you have the water muffs on a1984 omc stringer and hook the hose to it you should have water shooting out the trunion ports with the trunion caps off should you not??, just got the motor working good on this rebuild now the outdrive work starts. Will the water pressure pass through the pump without the pump turning? I have no water comming to the trunion ports.

Confused Frank