OMC cooling question

[shopmon2002]

I just purchased an almost mint condition 1971 Johnson Sea Horse 6hp. It had not been used in 15 years according to the guy selling it. I drained the old gas from the tank, put in some fresh fuel and it cranked on the 4th pull!! Idles well, no leaks anywhere, I am tickled pink. The water pump impellor, however, has obviously seized from sitting so long, because the engine was not pumping water. I've never replaced one of these before. Is it a tough job on this engine? Also, I found the water pump kit Sierra PN 18-3202, but it does not include any gaskets . Will I need any gaskets or other parts for this task? Any help would be appreciated!!

 

[Haffiman]

Re: OMC cooling question

Go here for a parts breakdown:
http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1971&hp=6

 

[JDusza]

Re: OMC cooling question

While you're in there, check water tube grommet 0302497.
J

 

[kbait]

Re: OMC cooling question

If the old impeller is in pieces, find all of 'em! Cooling can go haywire if a chunk has migrated up the watertube.

 

[mekkamaz]

Re: OMC cooling question

While working on the LU, Better to remove thermostat housing and replace t-stat. Flush from there and be secure there?s no pieces of impeller in the water circuit. For a motor that old I suggest a good maintenance before running and start having issues...carb, fuel pump, gear oil, spark plugs,

 

[kfa4303]

Re: OMC cooling question

HI shopmon. Here's a vid that can walk you through the job. It's for a 40 hp of similar vintage, but all the steps are basically the same. That's part of the appeal of these old OMC motors from the mid 50's- early 70's, once you can work on a 3hp you can pretty much work on anything up to 40 hp. You can the impeller itself right here at iboats for about $10. However, because the motor has been sitting so long, you might want to get a complete water pump rebuild kit, which comes with a couple extra grommets and seals. Give the vid a look see and holler if you get stuck. Good luck. Keep us posted.

http://www.youtube.com/watch?v=VnTx_WtUpig

 

[kfa4303]

Re: OMC cooling question

here's a great thread from a fellow iboater, with great pics and descriptions that should also help.

http://forums.iboats.com/showthread.php?t=528199&page=6

 

[AlTn]

Re: OMC cooling question

the lu on the 6 hp. comes off somewhat differently than other outboards..google...Leeroy's Ramblings....then go to his section on out outboard repair...6 hp....read before beginning if you are working w/o a manual...marineengine.com has diagrams of your motor ...also many postings here on replacing the impeller on the 6 hp. search for one that F_R has posted on < no slight to anyone intended >

 

[kfa4303]

Re: OMC cooling question

That's right :/ AlTn, do you have to remove the power head on those guys like the old 5.5/7.5 from the 50's? IF so here's a vid for that, which may be of some use also.

http://www.youtube.com/watch?v=SVOedhzPP7M

 

[AlTn]

Re: OMC cooling question

no....there's a pin at the top of the d/s that must be aligned with a slot before it'll drop...pay attention to the alignment of that pin as it comes out of the exhaust housing so you'll be at least close to that slot when you slip the lower unit back on...some "fenigglin" with the prop shaft or driveshaft will propbably be required when putting it back on to achieve this alignment, all the while you're trying to align the water tube and grommet..little aggrevating the first time you do one

 

[shopmon2002]

Re: OMC cooling question

Thanks for all of the replies! I have loosened the lu, but where is the access to the driveshaft pin? Thanks!

 

[tx1961whaler]

Re: OMC cooling question

Rotate the flywheel until the lower unit falls down. The pin is on the top of the driveshaft

 

[shopmon2002]

Re: OMC cooling question

Lu is off and impeller is installed. Where is the thermostat? Thanks in advance!!

 

[kfa4303]

Re: OMC cooling question

part #22. It's super simple to replace. just remove the old one, make sure the housing is nice and clear, then just drop in a new t-stat and grommet and voila! you're done.

 

[shopmon2002]

Re: OMC cooling question

So I pulled the tstat housing off, and there is no tstat there, just a hole for it. The new one I bought fits perfectly in that location though. Should I add the tstat, or put it back together without one? Thanks!

 

[Haffiman]

Re: OMC cooling question

If you want a nice idle, put it in!

 

[5150abf]

Re: OMC cooling question

While you are working on it avoid future problems by replacing all the fuel lines and get a fuel filter on it and yes replace the tstat, it was there for a reason, without it the engine will never warm up and won't run right.

 

[kfa4303]

Re: OMC cooling question

If you want a nice idle, put it in!

Ditto! These motors were designed with t-stats and the should be used whenever possible. I don't know why so many people fiddle with them and come up with elaborate theories as to why they should alter, or remove them, but they shouldn't. They help you motor run at it's best and couldn't be easier to replace. Just drop a new one in with a fresh grommet and you're good to go.

 

[shopmon2002]

Re: OMC cooling question

Just a follow up: got the impeller installed and the lower unit back in place. I replaced the tstat housing without the tstat, and just as predicted, the engine ran rough cold. I will drop the tstat in and all should be well. The water outlet has a strong stream of water, though, telling me my water pump overhaul was a success. I also intend to replace the pump filter and fuel lines as suggested. Thanks again for all of your help! This forum has saved me a costly repair bill.

 

[5150abf]

Re: OMC cooling question

The pump filter should be fine, I meant an inline filter, I have gotten lots of crap in my carb sith just the pump filter, it will keep out the really big stuff but even a cheapy Auto Zone in line will keep you from having to work on the carbs again for a very long time.