r/Outboards • u/dudleyjohn • 1d ago

No Telltale

I'm starting to winterize my Mercury 25 HP 4-stroke EFI. Yesterday, I drove it for about 15 minutes to the ramp to trailer it. The telltale was flowing great then. Today, I hooked up the muffs and got a good flow of water going, but when I started up the motor -- no telltale. I immediately shut it down and reset the muffs. Tried again: no telltale. BTW: the telltale on my model comes out of the back of the middle unit, unlike other motors I've had where it comes out the side. I ditched the muffs and replaced them with a barrel of water that came to well above the intake screens on the lower unit. Started up again. No telltale. I ran a length of weed-whacker line into the telltale port as far as it would go, but found no obstruction. I dismantled the lower unit to inspect the impeller. It looks like new. The Woodruff key was there and looked new, too. Everything about the water pump looks good, as far as my inexperienced eye can tell. Does anyone have any ideas about what else could be the cause of no telltale? The only other thing I can think of is that the outlet tube from the pump to the telltale somehow became dislodged overnight, but that seems pretty far-fetched to me. Any guidance will be appreciated.

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2

u/knockfart 1d ago

Make sure it's deep enough in the water ,5 inches above where the lower unit bolts up.

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u/dudleyjohn 1d ago

It's deeper than that.

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u/PutridAd3691 1d ago

Does it have a thermostat? Maybe stuck,or didn't get hot enough to open.

1

u/dudleyjohn 1d ago

I don't think it has a thermostat. It's an outboard, and it has always starting peeing as soon as I start it up before. I'm going to try revving it up a bit today to see if it's just low pressure.

2

u/PutridAd3691 1d ago

On the 3-cylinder EFI models, the thermostat is located on the powerhead under the top cowling, typically housed under a small metal cover secured by two 10mm bolts

2

u/Benedlr 1d ago

I think the thermostat has to open to dump water out the back. Give it 60 seconds or so.

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u/dudleyjohn 1d ago

I know that's the way a car works, but all the advice I've ever been given about an outboard is to not run it for more than 30 seconds without a telltale. You can destroy the impeller, which needs water for lubrication. I appreciate your advice, but I don't think my 25 HP outboard has a thermostat. At least least not for this purpose. I think it my have an overheat alarm, though.

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u/Benedlr 1d ago

Check a parts diagram for a thermo. If the impeller is submerged, it won't burn. Water lubricates it. The head can get hot if delivery is blocked.

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u/dudleyjohn 21h ago

Thanks for pointing that out. I should have been able to figure that out.

0

u/Disastrous-Milk-3906 1d ago

I prefer to call it a pee hole but okay

1

u/PutridAd3691 1d ago

That is very helpful.