Constant high pitch alarm?

[ShoestringMariner]

I just tried running a new to me 1990 Johnson 70 today. I let it warm up at the dock and then started out on the lake. Just as it came up on plane, a solid, high pitched alarm sounded (ear piercing, not a buzzer) and started on until I docked it and shut it down.

I just had a mechanic de-carb it and install a new thermostat. He used his controller.

Does this sound like a heat alarm or could it be vro which is disconnected?
Thanks

 

[racerone]

Did you unplug the wiring on the VRO?----Unplug the oil tank ?----Did you install a new water pump impeller ?----And you kept running your motor with the alarm sounding ??

 

[ShoestringMariner]

Did you unplug the wiring on the VRO?----Unplug the oil tank ?----Did you install a new water pump impeller ?----And you kept running your motor with the alarm sounding ??

VRO disconnected by previous owner, oil tank gone, No new impeller, Telltale was strong, and yes, I had to get back in. I turned around immediately.

 

[racerone]

Well-----I would now do a compression test.----Post the numbers.-----Does the tell tale hose come off the side of the engine block or off the top ??------Any time you put a " new to you " motor in service it needs a new impeller!

 

[ShoestringMariner]

Well-----I would now do a compression test.----Post the numbers.-----Does the tell tale hose come off the side of the engine block or off the top ??------Any time you put a " new to you " motor in service it needs a new impeller!

While normally I would agree and do this, I’m in the midst of a major health crisis. I neither had the wherewithal to perform or afford a new impeller. Dumb as it may be, I was planning on limping this motor through the season and doing it later. I need some water time while I deal with my fight.

Comp is reportedly ~105 across all three. Can’t recall where telltale hose originates. I think it comes from the side as hose crosses the back of the powerhead. I will look to confirm

Could I ask what compression has to do with it? That’s got me puzzled

 

[ShoestringMariner]

Well-----I would now do a compression test.----Post the numbers.-----Does the tell tale hose come off the side of the engine block or off the top ??------Any time you put a " new to you " motor in service it needs a new impeller!

And thank you for your help!

 

[racerone]

If it was the overheat alarm , you may have damaged the motor.-----Perhaps not the opinion you wanted to hear.----But it is what you need to act on.

 

[alldodge]

Not an OB guy but an alarm is going off non-stop but sensors are unplugged, how does that happen?

If its not overheating then it may just be an issue with the alarm and not the motor. Do find out if it is doing something to cause an alarm

 

[racerone]

When you unplug the VRO and oil tank the overheat horn is still in the circuit I believe.

 

[ShoestringMariner]

Ok guys, not sure if photos help. There’s a few disconnected plugs. Wondering if any should be unplugged?

Telltale is from the side of the block

 

[racerone]

There was a service bulletin in 1994 that was to move the telltale.---Water pump kit 0432955 has instructions for cooling system modification.

 

[ShoestringMariner]

There was a service bulletin in 1994 that was to move the telltale.---Water pump kit 0432955 has instructions for cooling system modification.

Yes, thank you.

 

[ShoestringMariner]

Coming back to this, so it is overheating. New thermostat, previous owner had it removed completely.
No tell tale mod.
Pee stream strong but getting hot, thermo housing too hot to touch.

Any thoughts on what I can do without pulling boat out of water? My park launches all boats at a cost and I’m very tight on money due to a health condition.

Anyone think I have a bad thermo or blockage?

What does telltale port mod do?

 

[Crosbyman]

likely blockage of water passages from a broken impeller fin or just accumulated crud. lake water or salt water engine ? ?


new impeller needed and pump housing must be inspected ... if lucky any broken parts may be lodged in there.

 

[Faztbullet]

Motor has to have a t-stat or restriction washer or it will overheat. "P" is a water pump indicator, doesnt mean it cooling.

 

[ShoestringMariner]

likely blockage of water passages from a broken impeller fin or just accumulated crud. lake water or salt water engine ? ?


new impeller needed and pump housing must be inspected ... if lucky any broken parts may be lodged in there.

Thanks, I’m starting to wonder about blockage. Either crud or impeller shrapnel. The aluminum boat it came with was completely covered with growth on the bottom (lake water) possibly zebra mussels.

 

[Crosbyman]

well zm are known do block inlet pipes to water filtration systems

could that have invaded a long sitting engine... maybe. but check the impeller theory first
and faztbullet comment

 

[ShoestringMariner]

Gonna pull the thermo this morning and see what that’s all about

 

[ShoestringMariner]

So I pulled the thermostat. Nothing stuck inside. No debris anywhere to be seen. I ran it while it was removed. Motor stays stone cold. no alarm. Telltale stream was not as strong. Absolute ton of water coming out of the blubber holes.

Next week I’m going to perform the telltail mod. And reinstall the thermostat. Wondering if I had an air pocket.
Could the spring temp/tension be incorrect?

 

[oldboat1]

The first thing I would want is to figure out if it is running hot -- got a hint at the t-stat housing, but should invest in an infrared tester when you can. Tops of heads should run around 140F or so. 165F is overheating.

Yes to your question re. the air pocket. That's why the bulletin called for rerouting to the top of the engine.