1986 Johnson V4 140 Looper - Overheating problem

Pappy is right, no diverters are used in this motor. It is a DIRTY mess. If I saw that water jacket on a motor here in Minnesota, I would use it for a boat anchor. Klink made a reasonable suggestion, clean as best as possible and then do a flush. Put thermostats in. The guy took them out because he was thinking it would help it run cooler.

Did you do a compression test before teardown? Its been substantially overheated. This all might be an exercise in futility. The piston rings might have surrendered.

racerone said:

Well,-----What does your factory manual say ?-------And does a parts breakdown of your motor show any diverters ??????------Note---- those head gaskets in post #25 are for a " crossflow " engine and you are working on a looper style engine.----Totally different machine.

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Good question. The shop manual doesn't distinguish between Loop-charged and cross-flow blocks, with regard to diverter/restrictor installation. It only distinguishes between "typical water passage restrictor" and "V4 water circulation and waterpassage restrictor" locations.

Also, I don't see diverters listed here at marineengine.com for this motor, but I also don't consistently find it shown for some known crossflow engines, either. Some yes, some no, so it has helped me remain confused. :-D

faztbullet said:

You have a looper 100%....no diverters in block

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Thanks for helping me nail that one down.

racerone said:

Is the water " control valve " still in operation on the side of the block , yes or no .

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I can't give a yes-or-no answer. How would I determine this?

timguy said:

Did you do a compression test before teardown? Its been substantially overheated. This all might be an exercise in futility. The piston rings might have surrendered.

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I had planned to. I tried to do the Advanced Auto tool loan, but they didn't have one to loan me. I will say, though, the engine runs really well. Good and smooth. Just getting hot. As for the scale in the water jacket... this motor has lived its entire life on the Gulf Coast - all salt & brackish water, so salt scale is par for the course. I'm cleaning it all up, as I go. Oh, BTW, the cylinder walls look good, too.

I'm starting to really scratch my head. I was hoping I had found the problem in the "missing" diverters/restrictors. That seems like a phantom at this point. I look forward to ferriting out the water control valve concern.

Which year " crossflow " --Did you come across where diverters were not shown in the parts book / pages.

racerone said:

Which year " crossflow " --Did you come across where diverters were not shown in the parts book / pages.

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Oh, man... don't get me to lying. I have looked at so many things... I know I saw the diverter on one of the 6 cylinder crossflow models, and I didn't see it on one of the 4 cylinder models, but I couldn't tell you which ones they were. I was poking around, kinda randomly looking for the diverters on "x" models and "L" models until I found one with the part number I was looking for.

I just retired a 50hp with similar issues and went through the entire cooling system and still couldn't find the issue till I decided to hook a hose straight to the copper water intake and wouldn't you know it, the salt corroded straight through the pipe so check it too if you find yourself still scratching your head.

relicshunter said:

I just retired a 50hp with similar issues and went through the entire cooling system and still couldn't find the issue till I decided to hook a hose straight to the copper water intake and wouldn't you know it, the salt corroded straight through the pipe so check it too if you find yourself still scratching your head.

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You know, that's not a bad idea at all. I might want to do that & just see where (if anywhere) the water is clogging or diverting. Did you use any special fittings to make the hose/tube connection?

TipDS said:

You know, that's not a bad idea at all. I might want to do that & just see where (if anywhere) the water is clogging or diverting. Did you use any special fittings to make the hose/tube connection?

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You need to find some hose or tubing that will fit on the garden hose at one end, and the motor pick up tube on the other. I made myself one of these "reductor/adapters" with a quick connect to the garden hose, and using a screw type clamp on the pick up tube (and you need to get it on there pretty tight or the water pressure will want to push the hose off the tube).
Also protect the electrical connection best you can so that they don't get splashed by water too bad while you check where the water is flowing out of.

I actually used a half inch camper RV hose with the end cut off and it fit snuggly, also only turn your hose up to equivalent to the pressure your motors pump produces.

faztbullet said:

It will overheat without the t-stat/poppet. The water valve works in combination with these to allow them to unseat at RPM. The heads will run on the hot side externally due to they very little flow thru them. Check valve to see if water is being switched thru it as if not the poppet wont fully unseat and run hot. Check the alarm to see if working.

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Is that possibly for models that have the thermostats located at the base of the powerhead? I don't believe mine has the poppet. Mine has two thermostat covers, one at the top of each cylinder head. Each one takes just a thermostat with a thermostat gasket, into which the thermostat screws. If I'm misinformed or misunderstanding, please let me know.

I'm still curious about how to check the water control valve for proper operation.

So, I've had a few folks propose a possible problem with the water control valve. Anybody know how to diagnose this?

Ok, no love on that question. I've been doing some research & found that eliminating the water control valve is an option, by updating the cooling system to the 1993+ design. Looks like I'll need:
333967 — COVER, THERMOSTAT STBD. (1 required per assembly)
329830 — GASKET, THERMOSTAT COVER (2 required per assembly)
333858 — SPRING, RELIEF VALVE (2 required per assembly)
333967 — COVER, THERMOSTAT, PORT (1 required per assembly)
And do this:

Does anyone here have any experience in doing this? If so, are there any pitfalls to watch for? Does it work well at all throttle ranges?

Ok, so I finally put off other projects to return to this one. As relicshunter suggested, I put the hose directly on the water tube. This was, of course, after I cleaned the water galleries as best I could and put the heads back on with new head gaskets. Ran the motor for around 20 minutes, and never got over 160 degrees F. On closer examination of the water pump, I noticed the "gromet" that goes into the pump housing, where the water tube "stabs" into the housing... the gromet was out of alignment, restricting the water flow some. I fixed that, adjusted my shift rod a couple times (to alleviate an issue I'd been having since purchase where I had to move the throttle to reverse, before I could disengage the forward gear) and put everything back together. With the thermostats in, I was still getting a bit high temps (around 180F), but not much more. I resigned myself to remove the thermostats, and that had me running around 160F on the muffs indefinitely. I don't feel like I've totally solved the issue, but it's to the point that I believe I can use the boat again, without fear of damaging the powerhead.

Might get hotter now, under load, with cowling in place and in the warmer gulf water. Keep us posted, brother.

Something strikes me as weird here.... you were running at 160 degrees (max) before fixing the water restriction caused by jammed water pump grommet, and after fixing the restriction, "around" 180 degrees?....
It's your motor, but I wouldn't feel comfortable running it under load without thermostats. Their job is to ensure temperature regulation stays where the motor performance (and longevity) is optimum.
I know that's not what you want to hear and I hope I'm wrong (been there myself before) but something tells me you still have a flow restriction somewhere in the power head....

Now that you have the motor cooling enough to run, get some "Salt Away" or other salt-dissolving solution.

Use a cheap plastic concrete mixing pan under the motor, available from Home Depot or Lowes, and put in a few gallons of the mix. Use a bilge pump and a hose going to the muffs, and run the engine. The pan should catch the mix, and the bilge pump will pump it back into the motor. Let it run for a half hour or so, let it soak for a while, then do it again, revving the engine briefly to help break up the crud inside.

You may have to do this several times to melt away the salt deposits inside, but if the stuff can get into there, it should work eventually. Keep this setup for future salt flushes. If you live in the gulf, you need to do this anyway!

Hope this helps.

-TH

Just wanted to update y'all. I've had the boat on the lake a few times & run out to Horn Island multiple times now. Not a hint of a cooling problem any longer. I have had it up to WOT for extended runs, just to test the cooling & it's been good. Hard to believe such a small issue (the misaligned sleeve in the water pump) could cause so much havoc. The change in water flow from the telltale was imperceptible, but I guess that thing isn't really in the actual cooling path, anyway. Seems half useless. Anyway, at least I got a better picture of my cooling chambers, and they got a good cleaning. That, and I have some new head gaskets. Thanks for all y'all's help.