Advice on starting '68 6HP Johnson after sitting for 10 years

[olympic]

Oldboat1, yes I had water coming out the rear outlet when pushing it up the tube when lower unit was off.

Makes me suspicious of something with lower unit as a result.

What still mystifies me is first two starts after sitting for 10 years had water. Only ran each for a minute because it then died. Third start no water so shut it down.

Replaced water pump impeller, no water. Take it apart to double check work, still no water and made sure plenty of water depth in the 33 gal garbage can.

Probably need to get that LU off again and run the drill test. Hopefully I can get it to come off this time.

 

[oldboat1]

Yes. Sounds like the water is circulating through the cooling passages in the head -- doesn't mean the t.stat is working correctly, but should get similar results pumping water using the l.u. pump. Think you are right -- probably likely the l.u., so try the drill test. (Don't ding up the driveshaft splines.) There should be a wear plate (stainless metal plate) under the impeller, and the cover should fit tightly on the plate (no cracks or chips in the housing). If spinning it with the drill doesn't produce, afraid disassembly would be needed to check it out. The likely problem is that the shaft key has'nt engaged (not spinning the impeller), as you are aware, but also can be a venting problem. Want to be sure that lower plate (wear plate) is installed correctly -- think there is only one way it fits in the housing, but would check it if you have to disassemble. When you get it pumping, you can check the running temp and think about the t.stat operation. You haven't gotten to the magneto issues yet, so more tinkering. Hopefully, will run well enough to insure it's pumping, and can go from there. So far, it's fair to say the water will circulate in the head properly, if you can get it up there. Lube the impeller end of the water tube a little, and make sure it fits snugly at the impeller housing (and that there is a rubber gasket in the housing to accept the tube -- not crimped or otherwise broken). Will check in tomorrow.

 

[olympic]

oldboat1, the lower plate under the impeller is there. I didn't even remove it and I think it would only fit one way so that should be good. It was nice and clean as well. There is a rubber grommet/gasket at the top of the water tube outlet in the pump housing where the upper copper water tube would fit into it. When I have it apart again I will double check it's condition, but I know it's there.

Last time I took it apart the impeller key was present and when putting it back together it was there and had to fit the impeller down over it so not sure why it wouldn't engage properly.

Well hopefully I can get that lower unit off tonight and get a drill test conducted. stay tuned....

 

[AlTn]

a suggestion..engine in the barrel...1.just remove the thermostat cover and pull the thermostat out...start the engine, is water being pumped up to that point?..if so, no need to pull the LU..if not...move on in your investigation....2.water level in barrel...fill it up to within a few inches of the exhaust relief ports < exhaust "nostrils">, sometimes that few more inches of water pressure seems to make a difference

 

[olympic]

Hey, was reading up on thermostat removal and came across this: http://www.leeroysramblings.com/OMC_6hp.htm I know that site has been cited in the top secret files. Anyhow, for those of you vested in my challenge here I found the section on "no overboard water indicator on early motors" on that web page to have some interesting insight. The following statement is intriguing:
"This outlet allows for some outlet water to mix with the exhaust gasses to cool the housing and at the same time allows only a small amount of exhaust with some spitting water, as an indicator of sorts, some may call it second exhaust port, however in actuality, in these smaller engines you could say it is an idle bypass, because at idle speeds there is not enough exhaust pressure to overcome the under-water pressure out the larger hole near the prop."

Based on the suggestions members here have given, it probably makes sense to remove the thermostat next just to confirm if I have water pumping to it before tackling the lower unit again. I just didn't realize that there was also a water outlet by the prop that might have water coming out even if not seeing anything from the exhaust port nostrils.

 

[oldboat1]

If feeling a little gutsy today, try the motor buttoned up, hood off. While running keep testing the temp on the top of the head with the heel of your hand. If you can keep your hand there for a few seconds, it's about right. If too hot to touch, shut it off. Most of the water does indeed pass out down the leg and out by the prop.

 

[olympic]

I went ahead and just fired it up filling the can to the top which had it just about to the grease fitting on this short shaft outboard. Just a very slight wisp of water coming out, mostly just exhaust. Same even when I put it in gear. Motor hot to the touch...can only leave hand there for not more than a second.

I think I'll let it cool down a bit and then pull the thermostat cover. Should I fish out the thermostat and leave the cover off, fire it and see if water comes pushing out at the thermostat housing? That's what I'm thinking so that I can first hand verify if water coming through there. Thanks.

 

[oldboat1]

think that's right. The t.stat may be stuck closed, or partially closed -- could be the bypass under there is partially blocked too, so good to poke around a little. Check with he cover off initially, like you say. If flowing up there, run it some without the t.stat (t.stat cover on, with old gasket -- might leak a little). Do the hand test while running. The t.stat should keep it at about 140F when in place and working, so should run colder without it. Best to keep a hose running in the barrel to keep the water fresh. Will get a good flush that way. If you find some corrosion around the t.stat well, scrape it out.

 

[olympic]

I pulled the thermostat cover and the thermostat itself, ran it for about 15-20 seconds...nothing. Bone dry up there. I suspect it should have pumped water in that amount of time, sound right? Assuming so then it looks like the lower unit needs to come back off. I really feel that I installed the impeller properly as its straight forward. Makes me wonder what else down there could cause issues. Warped housing? Maybe some sort of blockage in the lower area passages? Of course will double check impeller again and will try the drill test.

 

[oldboat1]

should have been water from the git go. When pulled apart again, might try that flush again just for grins -- satisfy yourself that it will get up from the water tube to the t.stat up on the head (then flush it downward through the t.stat opening). On the l.u., suggest the drill test first. If not pumping, and disassembling impeller assembly again, check under the wear plate for blockages too. Got to believe it's just a head slapper in assembling the impeller. If reinstalling, try twisting it on this time (impeller keyed in place, then rotate shaft clockwise while lowering cover.)

 

[olympic]

The weird part is that the impeller really only fits on one way with that key and the slot in the impeller, right? I made extra sure last time to rotate clockwise as it went down and then I turned the driveshaft manually and you could turn it and feel resistance. I could still turn it, but there was some resistance. Obviously something isn't correct through. Thinking through this, starting it after 10 years of sitting it pumped water for first two starts, then third start nothing. When I took impeller out with first disassembly of what had been in there for ten years, it looked fine. No broken tips or obvious signs of failure. I'll check under the wear plate this time to see how that looks. I'll also flush up and down to again to confirm water in both directions via that thermostat to make sure no blockages to it.

For the drill test, are there any tricks for not damaging the driveshaft? That is my only concern with the drill test. Thanks and I'll continue to post updates.

 

[oldboat1]

no tricks to that test. a little care, that's all. There was a thread last night on impellers with different key shafts (different from what I was aware of). Bottom line, though, is that they only go on one way, so kind of foolproof. Just have to be sure the key is catching the impeller hub. See what you come up with.

edit. suddenly struck me you are in Washington, 3 hrs. earlier than me (NY). may have to catch up with you tomorrow.

 

[olympic]

Got the lower unit off again this evening and noticed that the copper tube might not have been lined up properly. Hard to tell because of the way it drops, but from what I could tell it might not have been lined up. If that is the case it would explain no water.

I went ahead and ran a drill test. It takes a couple of seconds and then water comes out the water pump housing outlet tube at the top. It's coming out a good two or three inches high. Sound like enough? I didn't run it very long, just wanted to see if it is pumping and sure enough it appears to be. Assuming that is strong enough then perhaps it's truly just an issue with the copper tube not being lined up. I had tried to be very careful putting it together that it was lined up but of course tough to see that as it snaps together.

I welcome thoughts and based on feedback can once again slap together trying to be sure tube is lined up. Thanks!

 

[oldboat1]

think you've got it this time (or will know the reason). All good.

 

[olympic]

think you've got it this time (or will know the reason). All good.

Thanks. I went ahead and flushed down as well through thermostat and have water coming out the copper tube as well as the exhaust nostrils. I have a new thermostat gasket on order. Will try perhaps tomorrow eve to bolt the lower unit back on trying to make sure that copper tube stays lined up and see if I can finally get water through the engine.

 

[AlTn]

one thing that helps the water tube to slip into the grommet on top of the w/p is to put a film of grease on the outside wall <o/d> of the water tube while also putting a film of grease on the inside wall<i/d> of the grommet

 

[olympic]

one thing that helps the water tube to slip into the grommet on top of the w/p is to put a film of grease on the outside wall <o/d> of the water tube while also putting a film of grease on the inside wall<i/d> of the grommet

Thanks for the tip. I'll try that when reassembling.

 

[olympic]

Wanted to post an update. I haven't been able to put any time into this the past two days. This evening while I have thermostat off and lower unit out I flushed down and water readily comes out the tube and the exhaust nostrils. Now interestingly when I tried to flush up the water tube it didn't come out the thermostat area...it was almost acting plugged with water coming back out around where I was trying to put it in at bottom of tube. It's tough through trying to get water up that small tube inlet. Was trying to use my kids water balloon nozzle, maybe I didn't have enough pressure building. I can flush down so it shouldn't be blocked. I have gone ahead and bolted up the lower unit so tomorrow afternoon I'll get a chance to see if I have water. I made certain that the water tube was into the outlet on the water pump housing. Hopefully I'll have water tomorrow!

 

[HighTrim]

For future projects:

If a motor has been sitting that long. DO NOT run it like that until you go over the motor, especially the cooling system. No good will come from it. You got lucky, in that the original impeller remained intact. I have had motor brought to me that took me days to pick old chunks of rubber out of the cooling system from when someone tried to fire it up without first changing the impeller. You have to change it anyways, do it before you fire it. I have also encountered mud dauber nests, bees nests, etc.. in the water pump. If I had tried to fire it, it would have spread this debris through the cooling system. Again, not good.

I cannot think of any PRO to running a motor right away after it has been sitting a decade. Only many CONS.

Check compression first. If compression is good, then go ahead and put the money into the tune up. Then run it. Im just trying to save you major headaches. A lot of times, nothing catastrophic will happen, but there are the times that it does.

When you reinstall the gearcase, as stated, grease the copper water line, and the grommet, to allow the water line to slide in smooth without binding and pinching. That is a very common spot where water flow is restricted.

Remove the plugs. Put the motor into forward gear. Put the gearcase into reverse. This gets the shift rod connection out of the way while you slide it up. Slide up gearcase, and first ensure water tube slides up straight into the grommet. Then push up. If it stops short, rotate prop, to align splines, and it should slide up the final amount. Put in a bolt. Hook up shift rod, and test all gears. If all is well, install final bolts. On your model, you also have the pin to align with the slot as you know. Never forget this pin, or you will get water into your powerhead.

Removing plugs is a safety note. It is possible, for it to fire while rotating the prop. Small chance, but could happen. Don't want your hand there if she fires up!

 

[olympic]

I appear to have water as I didn't run it but a couple seconds and had water shooting up through thermostat housing. As a result I went ahead and just put thermostat and gasket in. Will let that sit overnight and verify tomorrow good water. Just ordered a fuel filter cap (sits on top of fuel pump) as found current one has hairline crack - thought it was just gasket but not that lucky.