1982 Johnson 50 Sea Horse - Constant Beep While Accelerating

Crosbyman

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great news thanks for your feedback. :) Happy fishing ! here the ice cubes get in the way.
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tphoyt

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I mentioned not long ago I haven’t seen any ice in the harbors for years. I jinxed myself. Been in a deep freeze for over a week now. Makes for good pond hockey though. It looks like a warming spell in moving in for the weekend.
 

Elessar_94

Seaman
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Nov 27, 2024
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I mentioned not long ago I haven’t seen any ice in the harbors for years. I jinxed myself. Been in a deep freeze for over a week now. Makes for good pond hockey though. It looks like a warming spell in moving in for the weekend.
😂 Been eyeing the forecast - 56 and partly sunny on Sunday in South Carolina. Should be a great day to get out on the water! Cold front next week though.
 

saltchuckmatt

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Jul 19, 2019
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I mentioned not long ago I haven’t seen any ice in the harbors for years. I jinxed myself. Been in a deep freeze for over a week now. Makes for good pond hockey though. It looks like a warming spell in moving in for the weekend.
Ahhhh.....pond hockey and lobster rolls.....what could be better!
 

Elessar_94

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Nov 27, 2024
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Hey everyone,

I hate to revive this thread after we thought we had it solved but I'm still getting an overheat alarm under load (it's quieter now with the new water pump, but still there). Cylinder heads still feel hot though not quite as hot as before we changed the water pump. I can't touch them for longer than a second or two. The telltale stream is STRONG, so that's good at least.

The only things I can think of now are to check inside the cylinder heads themselves as well as the water passage for salt buildup and/or a blown head gasket. I have sourced both gaskets and they are fairly inexpensive. Will post another update once I replace those items and do a lake test but I wanted to confirm this course of action with you all first...

Proceed as planned or do you have any other suggestions at this time?
 
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Elessar_94

Seaman
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Nov 27, 2024
Messages
65
don't want to read 88 posts bt have you tried flushing using stuff like SALT AWAY etc...
No I haven't tried that yet, but good idea. I don't have a tank large enough but I see this can be done using a mixing unit connected to muffs so maybe I should try that first before opening everything up:


(For some reason, the voice audio in this video only comes out the right speaker so you may need a stereo setup to hear it)
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,411
Cylinder head will be warped.----They all are with age.----Refinish it with emery paper on glass , before installing a new head gasket.
 

saltchuckmatt

Commander
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Jul 19, 2019
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I use salt away.... saltchuckmatt.

For a less expensive way....get a plastic barrel and put a couple of jugs of vinegar mixed with water. Run it at idle (if it will without overheating) for 1/2 hour or so and shut it off.

Let it sit for a week then test again.

Didn't you already pull your heads?
Latest compression test?

I had a hunk of salt come out of my 90 hp years ago that was huge!
 
Joined
Jan 17, 2019
Messages
933
Hey everyone,

I hate to revive this thread after we thought we had it solved but I'm still getting an overheat alarm under load (it's quieter now with the new water pump, but still there). Cylinder heads still feel hot though not quite as hot as before we changed the water pump. I can't touch them for longer than a second or two. The telltale stream is STRONG, so that's good at least.

The only things I can think of now are to check inside the cylinder heads themselves as well as the water passage for salt buildup and/or a blown head gasket. I have sourced both gaskets and they are fairly inexpensive. Will post another update once I replace those items and do a lake test but I wanted to confirm this course of action with you all first...

Proceed as planned or do you have any other suggestions at this time?
these particular motors will run on the verge of overheating if one or both lower exhaust seals are leaking. especially the upper one if that leaks/gets pinched, it will get hot. there needs to be a "wall of water" cooling the exhaust which is impossible without the seal. easy way to tell if this is the case though: after about 5 min of idling, does water spray out the 2 exhaust relief holes yes or no? this signifies the poppet valves are sealing properly when no water comes out. ditto for t stat. but when the t stat opens water should come out! at high speed the poppet valves come off their seats and dump water. id get a $12 IR temp gun of amazon and check the flat spot top of the head. needs to be between 125-155f there. not the middle. not the bottom. flat spot on top. 2nd possiblity but still almost as common: since this motor got hot, it could be melted the water tube grommet under the powerhead, or its just crusty ad swollen 2/3 shut making it overheat at higher speed/pressures. as suggested head gasket is easy to do and check for water intrusion as well.
 

Elessar_94

Seaman
Joined
Nov 27, 2024
Messages
65
these particular motors will run on the verge of overheating if one or both lower exhaust seals are leaking. especially the upper one if that leaks/gets pinched, it will get hot. there needs to be a "wall of water" cooling the exhaust which is impossible without the seal. easy way to tell if this is the case though: after about 5 min of idling, does water spray out the 2 exhaust relief holes yes or no? this signifies the poppet valves are sealing properly when no water comes out. ditto for t stat. but when the t stat opens water should come out! at high speed the poppet valves come off their seats and dump water. id get a $12 IR temp gun of amazon and check the flat spot top of the head. needs to be between 125-155f there. not the middle. not the bottom. flat spot on top. 2nd possiblity but still almost as common: since this motor got hot, it could be melted the water tube grommet under the powerhead, or its just crusty ad swollen 2/3 shut making it overheat at higher speed/pressures. as suggested head gasket is easy to do and check for water intrusion as well.
Roger that. I’ve never seen water come out of the exhaust slits but I’ll check next time. I installed a brand new thermostat and poppet valve grommet recently. The poppet valve itself was in perfect condition. I will for sure bring a temp gun next time to scan the cylinder head too and report the temps back here.
 

Elessar_94

Seaman
Joined
Nov 27, 2024
Messages
65
I use salt away.... saltchuckmatt.

For a less expensive way....get a plastic barrel and put a couple of jugs of vinegar mixed with water. Run it at idle (if it will without overheating) for 1/2 hour or so and shut it off.

Let it sit for a week then test again.

Didn't you already pull your heads?
Latest compression test?

I had a hunk of salt come out of my 90 hp years ago that was huge!
I pulled the cylinder head cover (water jacket) but not the cylinder head itself. I don’t have a pressure gauge but I’ve been meaning to get one. I was told when I bought it there was 140 psi in each cylinder but who knows if that’s still the case.
 

saltchuckmatt

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Jul 19, 2019
Messages
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Well if your having trouble getting the bolts out then I'd pickel it in vinegar and see what happens.

When I'm working on salted out small outboards, I pull the gearcase, turn the motor upside down, pour salt away down the water pump tube and let it fill the powerhead.

Not perfect but helps.

Nothing like a barrel full of old two stroke oil and rinse water to keep that engine clean inside.
 

Elessar_94

Seaman
Joined
Nov 27, 2024
Messages
65
Well if your having trouble getting the bolts out then I'd pickel it in vinegar and see what happens.

When I'm working on salted out small outboards, I pull the gearcase, turn the motor upside down, pour salt away down the water pump tube and let it fill the powerhead.

Not perfect but helps.

Nothing like a barrel full of old two stroke oil and rinse water to keep that engine clean inside.
Bolts in the cylinder head should be OK (hopefully). I’ve heard that flushing the motor will help prevent salt buildup, but if there’s already a clog, the best thing to do is open it up and chisel away at it. I’m still trying to decide how I want to approach this. Probably would be easier to start with a good flush and go from there like a few of you have mentioned.
 

saltchuckmatt

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Bolts in the cylinder head should be OK (hopefully). I’ve heard that flushing the motor will help prevent salt buildup, but if there’s already a clog, the best thing to do is open it up and chisel away at it. I’m still trying to decide how I want to approach this. Probably would be easier to start with a good flush and go from there like a few of you have mentioned.
Does your motor overheat at idle? If so then yes pulling it apart will be better.

Stuff can get hard as concrete.
 

Elessar_94

Seaman
Joined
Nov 27, 2024
Messages
65
Does your motor overheat at idle? If so then yes pulling it apart will be better.

Stuff can get hard as concrete.
Nope, runs perfectly fine at idle. It's not until I start accelerating past, say, 2000/2500 RPMs or so that the high-pitch ringing sound starts. It was very faint this time, almost inaudible. Changing the water pump seems to have helped a lot. It only overheats when under load at speed.
 
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