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

[racerone]

Water must be well above ( 6 " or more ) the pump in a test tank / barrel / bucket.----A common mistake is to just put water up to the intake holes !--The little pin was replaced ?---It drives the mechanical seal under the engine block and is important.

 

[oldboat1]

I like to run water up from the bottom, using the water tube (hand pump). Allows some checking with the motor off, and some flushing. If the water doesn't circulate out into the leg, there is a blockage up top. Need a fuel hose or similar that fits snugly over the water tube.

 

[olympic]

Water must be well above ( 6 " or more ) the pump in a test tank / barrel / bucket.----A common mistake is to just put water up to the intake holes !--The little pin was replaced ?---It drives the mechanical seal under the engine block and is important.

I think I was deep enough. I'm using a 33 gal garbage can and the water level was about 4 inches above the anti-cavitation plate. I'll double check things and if all looks good I can try putting it back together and see if I can get it to sit any deeper.

If you are referring to the driveshaft pin, yes I was able to drive the old one out and then drive it back in. Had to move flywheel slightly until it aligned properly to get the LU to go all the way back up in there.

 

[racerone]

Water must be about 6" above the pump !,--------------- not the cavitation plate.

 

[olympic]

Water must be about 6" above the pump !,--------------- not the cavitation plate.

Okay, I'll double check things, put it back together, and get water as high as I can to see if that is the difference maker. Thanks.

 

[oldboat1]

will belabor the point a little, but if pulling off the l.u. again (reasonable), do the flush test before reassembling if you can. With stored motors, there is the possibility of all kinds of critters making a home up there (mud wasps probably the worst). Take a flashlight and peek up into the leg from the bottom to see if there are any nests up there. (mud dauber nests disintegrate into fine sandy material).

 

[olympic]

will belabor the point a little, but if pulling off the l.u. again (reasonable), do the flush test before reassembling if you can.

Thanks. Okay, will take a look as yes I have the LU off right now. I will have to read up on the flush test. I wasn't sure if I can push some air through it or if that is too extreme and if I should just try to get water up that such as with a hose.

 

[oldboat1]

need low pressure for that water flush -- just enough to push up, around and through. Don't blast it out. Water flush is better IMO as it has a chance of washing out debris (like that stuff I mentioned above). But clearing with a little air is better than nothing.

 

[olympic]

need low pressure for that water flush -- just enough to push up, around and through. Don't blast it out. Water flush is better IMO as it has a chance of washing out debris (like that stuff I mentioned above). But clearing with a little air is better than nothing.

Thanks again for the continued help! I'll go back out and double check my LU work and then see about flushing things out, then put it all back together and get it as deep in the can as I can to see if I get any water.

 

[olympic]

Okay, this shouldn't be this hard. Still not getting any water. I dropped the lower unit and verified the impeller key and impeller looked good. I ran air and water both through the lower unit to flush that out. I then flushed the top as well. The nozzle my kids attach to the end of the hose to fill water balloons worked great to push water up through the copper water tube. All that seemed okay.

I then reassembled the impeller housing, turned it clockwise to verify some resistance. It turns pretty easily, but there is resistance. I installed the lower unit, filled the garbage can again to the top this time so it's a good 8 inches of water depth above the anti-cavitation plate, fire it up, but no water. I see just a wisp of water and that could be the exhaust or something pushing out what was in there from the flush.

So I'm a bit puzzled here. Thinking back to a week ago, starting it for first time in 10 years (always stored in a garage) it fired right up and spit water pretty well for the first two times I fired it. Third time to no water. I have since changed the impeller and ran water through it, but still not getting any water at the outlet when running.

In the barrel I did try putting it in forward and reverse for a few seconds just to see if either of those gave enough current to push water into the inlet but no difference in the water outlet.

Any other thoughts on this? Thanks

 

[oldboat1]

getting your ticket punched, olympic. In taking the lower unit off yet again (blindfolded, maybe, just for grins), might put it in the tub or barrel deep enough to cover the inlets, then turn the driveshaft clockwise with an electric drill. Can see if there is water pushed up from the pump (should be a good, steady flow).

edit. also can remove the t.stat and cover, and see if water is getting up there (either with that flushing rig, or cranking the motor). If doing that, check the t.stat to see if it is operating -- will likely need another gasket, but maybe not. It's a thick gasket, and kind of a difficult seal, in my opinion. If water is getting up there, could replace the t.stat cover and run it a bit without a t.stat -- if STILL no water moving through, know the blockage is beyond the t.stat.

(If it's still together, try the t.stat thing first -- hard to believe from your description the pump isn't working -- but still possible.)

 

[olympic]

Yeah, getting pretty good at dropping that LU. I'll try spinning the driveshaft with my drill and see if the pump is working. I'll report back. Thanks

 

[oldboat1]

Yeah, getting pretty good at dropping that LU. I'll try spinning the driveshaft with my drill and see if the pump is working. I'll report back. Thanks

but if still together, might try the t.stat test first (above). Editing while you were responding....

 

[ondarvr]

Check the compression, if the head gasket leaks it can pressurize the water jacket and over power the water pump, which can limit the amount of water flowing through the block.

 

[olympic]

I should have know better than to think dropping the LU would be getting easier. For some reason the lower unit doesn't want to drop this time. I can get it to free up the typical small amount after removing the four bolts, just enough to get the shift linkage bolt out. However after taking that out it's still hung up. That happened to me one other time and I just had to rotate the flywheel a bit and then it would drop down. I think it's a matter of that driveshaft pin lining up correctly and then allowing it to slip down. Well, I tried for 20 minutes to get it to drop slowing rotating flywheel without success. So, for now have bolted it back together. I'll check compression and do a t-stat test probably tomorrow. If those are inconclusive then I will try once again to remove the LU for the pump test. Thanks!

 

[oldboat1]

a plan. progress either way.

 

[olympic]

Just ran a compression test. I got 71 on one cylinder and 66 on the other. The motor was cold as it's been about 4 hours since I ran it briefly. I had the choke closed and had it in the "stop" position to keep any ignition spark from going. I grounded the plug wire being tested anyhow as a precaution. If the throttle should have been open let me know and I can re-test.

Are those figures low? If so, are they low enough to be indicative of a possible head gasket issue? I know my big motor is something like 105-110 across the cylinders if I recall correctly.

 

[ondarvr]

The choke should be open not closed, but it's not a huge issue. The number doesn't mean much because different gauges can give very different readings, also these motors tend have lower readings, plus when using a rope start motor the numbers are normally lower. You want them to be even, it doesn't rule out a leaking gasket, it would need to be a slight leak though.

 

[olympic]

The choke should be open not closed, but it's not a huge issue. The number doesn't mean much because different gauges can give very different readings, also these motors tend have lower readings, plus when using a rope start motor the numbers are normally lower. You want them to be even, it doesn't rule out a leaking gasket, it would need to be a slight leak though.

Okay. Based on the numbers though it sounds like minor leak if any so am I correct then in assuming that likely the head gasket is not leaking so much that it should be overpowering the water pump? If that is more likely than not the case, then I will continue to to the thermostat and then try again to drop lower unit to see if I can drill test the pump. Thanks

 

[oldboat1]

Compression on the little ones (good running little ones) is pretty low, and yours has been unused for 10 years. I wouldn't switch out a head gasket based on those readings alone -- would try to get it up and running, then retest (either hot or cold). Reasonably close between cylinders. My opinion, of course.

Think I would continue to look for a blockage first. You may end up taking off the head anyway to clear water passages, and would replace the gasket at that point.

losing track a little -- When pushing water up through the tube, did you get it exiting out down the leg and out of the exhaust port?