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Author Topic:   Tell-tale on a 1981 Johnson 35-HP Outboard

skred posted 03-14-2014 10:53 AM ET (US)
I've spent about an hour searching (with no luck) for one concise answer to this question: does my 1981 Johnson 35-HP two-cylinder two-stroke outboard have any other cooling tell-tale than the two openings halfway down the rear of the shaft housing? Those openings do spit water (spray, actually) when the motor is run. I can find no sign of an opening in the lower cowl where one would normally see a confidence stream.

Tom W Clark posted 03-14-2014 11:06 AM ET (US)
Yes, a 1981 Johnson 35 has a tell-tale. It is visible in the exploded parts diagram here:
http://www.boats.net/parts/search/BRP/JOHNSON/1981/J35ELCIG/ MOTOR%20COVER-JOHNSON/parts.html
Call-out item # 40 is the plastic nipple for the tell-tale rubber hose, which comes from the port side of the power head.
With age that plastic nipple becomes brittle so someone may have simply plugged or capped the hose instead of replacing the nipple.
jcdawg83 posted 03-14-2014 02:07 PM ET (US)
I had a 25hp Evinrude whose confidence stream tube would get clogged by insects nesting in it if it sat up for a while. A small, stiff piece of wire would usually clear it.
skred posted 03-14-2014 02:37 PM ET (US)
Found the hose and the nipple: Thanks for the help, Tom. I ran a thin wire up the hose: it seemed to go all the way to the block after I measured it. I just never noticed anything coming out when I ran it in a water barrel last fall. Ran fine, and although it seemed the cylinder heads were pretty warm, they weren't setting off the alarm. The dealer told me the fuel pump and the water pump were replaced when I bought it. I want to take the hose off at the engine to verify it's clear, but I don't know what kind of clamp it's held on with: looks a bit strange. I suppose I could replace the clamp with a hardware store variation... ?
It's a fresh water engine, so I don't believe there's any salt buildup.
Tom W Clark posted 03-14-2014 03:18 PM ET (US)

quote:
I want to take the hose off at the engine to verify it's clear...
Which hose? At what point on the engine?
Tom W Clark posted 03-14-2014 03:28 PM ET (US)
The human hand can tolerate temperatures up to about 125 degrees, the temperature at which this motor begins to be "warmed up".
Until the temperature exceeds 160 or 170 degrees, it is in the normal range and not overheating.
Use a hand held Infrared thermometer to scan the powerhead for hot spots if you are concerned about it overheating.
skred posted 03-15-2014 09:20 AM ET (US)
Thanks for all the helpful info, Tom. I should clarify that the motor does not appear to be overheating when operating. I was (am) more concerned with what appears to be the lack of water exiting from the "pee-hole". Perhaps I simply didn't notice it.
The hose referred to is the rubber hose connected to the top port side rear of the engine block (tapped into the water jacket). The hose runs across the top of the cylinder heads and diagonally down on the starboard side of the block, and attaches to the nipple which allows the water to exit on the underside of the lower cowling.
My research has indicated that if I can hold my hand on the cylinder head when it is fully warmed up (to your reference of about 125 degrees), and count 1-2-3 at a moderate speed, it is not in an overheat situation.
Binkster posted 03-15-2014 09:44 AM ET (US)
As far as Tom's comment on the infrared hand held thermometer, its a handy tool. I wouldn't be without one. You can look for hot spots on the heads and block on your outboard, check the temp of food in the oven, check the temp of the air or heat in the A/C unit by just pointing it at the vents, check the temp of the A/C in your car etc. Here is the one I have;
http://www.harborfreight.com/infrared-thermometer-93984.html
If you can find a 25% coupon it only $15.
I had a 1978 25hp Evinrude that is basically the same outboard. Bought it brand new back then and ran it on a 13 ft. Whaler. We used to take it to the keys for diving, and it seems the water is extra salty there. After I towed it home to Ft.Myers, and the next day when flushing it out I always had to run a piece of wire through the pee tube, as the salt was crystallized, the tube had a narrow diameter.
rich
skred posted 03-16-2014 08:57 AM ET (US)
Thanks, Bink. I'm waiting for midweek here, when the temps get enough above freezing to test the motor again.
skred posted 03-17-2014 08:19 AM ET (US)
A slightly embarrassing observation: The reason for my original question arose because (as I discovered later) the hose leading from the engine block to the exit nipple was painted the same color as the entire engine. I thought it was an electrical cable. So, if I want to disconnect the hose to check that it's clear, can I use a standard (albeit very small) hardware store clamp to re-connect it?
Tom W Clark posted 03-17-2014 10:30 AM ET (US)
The last time replaced that hose I just used a zip tie.
skred posted 03-18-2014 09:02 AM ET (US)
Thanks, Tom. It's obviously a somewhat lower-pressure situration, then.

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Author	Topic: Tell-tale on a 1981 Johnson 35-HP Outboard
skred	posted 03-14-2014 10:53 AM ET (US) I've spent about an hour searching (with no luck) for one concise answer to this question: does my 1981 Johnson 35-HP two-cylinder two-stroke outboard have any other cooling tell-tale than the two openings halfway down the rear of the shaft housing? Those openings do spit water (spray, actually) when the motor is run. I can find no sign of an opening in the lower cowl where one would normally see a confidence stream.
Tom W Clark	posted 03-14-2014 11:06 AM ET (US) Yes, a 1981 Johnson 35 has a tell-tale. It is visible in the exploded parts diagram here: http://www.boats.net/parts/search/BRP/JOHNSON/1981/J35ELCIG/ MOTOR%20COVER-JOHNSON/parts.html Call-out item # 40 is the plastic nipple for the tell-tale rubber hose, which comes from the port side of the power head. With age that plastic nipple becomes brittle so someone may have simply plugged or capped the hose instead of replacing the nipple.
jcdawg83	posted 03-14-2014 02:07 PM ET (US) I had a 25hp Evinrude whose confidence stream tube would get clogged by insects nesting in it if it sat up for a while. A small, stiff piece of wire would usually clear it.
skred	posted 03-14-2014 02:37 PM ET (US) Found the hose and the nipple: Thanks for the help, Tom. I ran a thin wire up the hose: it seemed to go all the way to the block after I measured it. I just never noticed anything coming out when I ran it in a water barrel last fall. Ran fine, and although it seemed the cylinder heads were pretty warm, they weren't setting off the alarm. The dealer told me the fuel pump and the water pump were replaced when I bought it. I want to take the hose off at the engine to verify it's clear, but I don't know what kind of clamp it's held on with: looks a bit strange. I suppose I could replace the clamp with a hardware store variation... ? It's a fresh water engine, so I don't believe there's any salt buildup.
Tom W Clark	posted 03-14-2014 03:18 PM ET (US) quote: I want to take the hose off at the engine to verify it's clear... Which hose? At what point on the engine?
Tom W Clark	posted 03-14-2014 03:28 PM ET (US) The human hand can tolerate temperatures up to about 125 degrees, the temperature at which this motor begins to be "warmed up". Until the temperature exceeds 160 or 170 degrees, it is in the normal range and not overheating. Use a hand held Infrared thermometer to scan the powerhead for hot spots if you are concerned about it overheating.
skred	posted 03-15-2014 09:20 AM ET (US) Thanks for all the helpful info, Tom. I should clarify that the motor does not appear to be overheating when operating. I was (am) more concerned with what appears to be the lack of water exiting from the "pee-hole". Perhaps I simply didn't notice it. The hose referred to is the rubber hose connected to the top port side rear of the engine block (tapped into the water jacket). The hose runs across the top of the cylinder heads and diagonally down on the starboard side of the block, and attaches to the nipple which allows the water to exit on the underside of the lower cowling. My research has indicated that if I can hold my hand on the cylinder head when it is fully warmed up (to your reference of about 125 degrees), and count 1-2-3 at a moderate speed, it is not in an overheat situation.
Binkster	posted 03-15-2014 09:44 AM ET (US) As far as Tom's comment on the infrared hand held thermometer, its a handy tool. I wouldn't be without one. You can look for hot spots on the heads and block on your outboard, check the temp of food in the oven, check the temp of the air or heat in the A/C unit by just pointing it at the vents, check the temp of the A/C in your car etc. Here is the one I have; http://www.harborfreight.com/infrared-thermometer-93984.html If you can find a 25% coupon it only $15. I had a 1978 25hp Evinrude that is basically the same outboard. Bought it brand new back then and ran it on a 13 ft. Whaler. We used to take it to the keys for diving, and it seems the water is extra salty there. After I towed it home to Ft.Myers, and the next day when flushing it out I always had to run a piece of wire through the pee tube, as the salt was crystallized, the tube had a narrow diameter. rich
skred	posted 03-16-2014 08:57 AM ET (US) Thanks, Bink. I'm waiting for midweek here, when the temps get enough above freezing to test the motor again.
skred	posted 03-17-2014 08:19 AM ET (US) A slightly embarrassing observation: The reason for my original question arose because (as I discovered later) the hose leading from the engine block to the exit nipple was painted the same color as the entire engine. I thought it was an electrical cable. So, if I want to disconnect the hose to check that it's clear, can I use a standard (albeit very small) hardware store clamp to re-connect it?
Tom W Clark	posted 03-17-2014 10:30 AM ET (US) The last time replaced that hose I just used a zip tie.
skred	posted 03-18-2014 09:02 AM ET (US) Thanks, Tom. It's obviously a somewhat lower-pressure situration, then.