Logo
FULL SITE MENU

delayed tell tale

F

fishingjim48

New member
Just bought a 1998 200 hp Mercury outboard, my question is, when I start the motor it takes a minute or two before the tell tale water shoot starts going.
Is that normal for that year? Thank You
 
Best idea ever. You know if the thermostat and the water pump are working. You know right away if a poppet valve is stuck or a thermostat is not working properly, and the.water pump is working at the same time. Why would.you want to modify that? There was a time that motors did not have pee holes and people.just replaced their.impeller regularily.
 
Last edited:
My son had a late '90's 150 and we didn't like the idea that you had to wait to see if you had water, something we wanted to know immediately when one does the initial starting while still on the trailer.....so that if you had a problem you could pull off the ramp and investigate.

I tapped into the hose on top of the block that has raw block water going down under the powerhead to the poppet valve and attached the tell tale hose there.

Yeah there are risks doing it both ways. We chose our method. In my current boat I installed a water temp gauge in the little ⅛" brass plug on the water jacket cover. I don't have to worry about engine temp as regardless of anything, I know the temperature of the powerhead.....just like the OT sensor mounted in the same plate knows the temperature of the powerhead/engine block.

Seems water pressure monitoring is popular and folks have a pressure gauge on the dash plumbed off the same port as I used. Fine. You have your reasons, I have mine! You have your operating conditions, I have mine!
 
Last edited:
Today's motors use higher pressure pumps. Rubber is not real rubber anymore. They are engineered failures. They have to be closely monitored.
C' mon we are paying up to $20,000 bucks and even more for these outboards. Why won't they engineer a foolproof water pump? The water pump on my 1969 Chevy pickup has been cooling the 400 engine for 38 years.....it cost $20 bucks. It does not have a synthetic rubber impeller.
 
Last edited:
timguy said:
Today's motors use higher pressure pumps. Rubber is not real rubber anymore. They are engineered failures. They have to be closely monitored.
C' mon we are paying up to $20,000 bucks and even more for these outboards. Why won't they engineer a foolproof water pump? The water pump on my 1969 Chevy pickup has been cooling the 400 engine for 38 years.....it cost $20 bucks. It does not have a synthetic rubber impeller.
Click to expand...

Your Chebby has a centrifugal pump in a closed system. Your outboard had a combination displacement/centrifugal pump. At low speeds the rubber is in complete contact with the walls of an eccentric chamber which fills with water on the larger portion and as the blades rotate they compress it in the smaller part of the chamber, thus providing the pressure increase.

At high speeds, (per OEM published data) the pump becomes a centrifugal pump, blades no longer contact walls of the pump since the water inlet is changing and the engine has a limited amount of flow capacity and cooling requirement with the pressure in the block running around 2-4 PSI at idle to 10-15 at WOT, with variable discharge ability depending on whether or not the stat is open or the popoff valve is off it's seat....if so equipped or something to that effect.
 
Right, good info. Point to be made is that it doesn't take "rocket science" to create reliable cooling for an outboard motor. As the motor speed and load increases, we need more circulation, but we know, of course, the boat is moving through the water, changing surrounding pressure on the water intake area. This will change with boat direction as well. Our engineers are relying on synthetic rubber impellers that are a "given failure". Protection of
very costly motors is based on warning systems, rather than solid, reliable engineering. I have a problem with that.
 
Before the days of alarms, I had a 70 hp Evinrude sieze up on me at WOT. Cost me a block because the stat froze shut; nothing to do with the impeller. Back then the www wasn't around and my previous engines just ran and ran. Never changed anything, nor even thought about it, but spark plugs. In today's world, being much older, more experienced, and hopefully wiser, I decided I didn't want to worry about cooling so I accessed the block water via the ⅛" brass pipe plug port and inserted a thermometer. My dash panel had an unused circle...for the old flasher depth finders I guess, so I stuck a 2" diameter thermometer there and quit worrying about engine temp.
 
Back in those days we had REAL rubber. This stuff now is garbage. My 1954 Johnson 5 1/2 Sea Horse has the ORIGINAL IMPELLER. I use it regularly. Don't want to put in a new impeller because they are crap. Here is a 56 year old impeller I recently replaced from a 18 hp Johnson. It's still perfect but customer demanded replacement. The new one is not as reliable as this one here. It's sad, my friend. IMG_20200724_100403465_compress44.jpg
 
Last edited:
timguy said:
Back in those days we had REAL rubber. This stuff now is garbage. My 1954 Johnson 5 1/2 Sea Horse has the ORIGINAL IMPELLER. I use it regularly. Don't want to put in a new impeller because they are crap. Here is a 56 year old impeller I recently replaced from a 18 hp Johnson. It's still perfect but customer demanded replacement. The new one is not as reliable as this one here. It's sad, my friend.View attachment 24284
Click to expand...

One difference is brass vs plastic key slot/ crank shaft adapter. Everyone seems to have their way of dealing with the water pump. Personally, I don't fix it if it works....just asking for some other kind of trouble. Course I boat in protected water, maybe 5 miles the longest trip on calm days in man made lakes, no salt water, no long trips out into the ocean, no paying customers.
 
I guess a few ounces of brass is too costly to include in the engineering on a $25,000 outboard. I boat in remote NW Ontario where a mechanical failure could lead to huge problems. I run twin motors, even though I am ultra careful and test my equipment regularly. Born and raised in remote territories. Been there, done that, still do it. Stupid.....maybe, but at least if something breaks, I know who to blame.
 
If you use the EMP brand impeller you will be getting the SAME impeller and rubber used 50 years ago. Winston and his crew made the impellers for OMC and has branched off into other brands. They also make the OEM carb kits for them.. I use EMP and Seirra all the time. Mallory,GLM and several other use a softer rubber which actually helps in pressure. A Mallory impeller in a Johnson V4-V6 will picked up about 2 psi at idle and 4 psi at WOT..
 
Last edited:
Excellent information Pappy, thanks. It's obvious you and I are still actively repairing. Just wondering if the rubber compositions have been modified to reduce costs? Pure rubber is expensive. Latex comes from over 200 kinds of plants, but the real....good stuff.....comes from rubber trees (Hevea brasiliensis), found almost exclusively in the far East.
 
Last edited:
Just to all another note.......even Coca Cola modifies their recipe......based on what the public seems to like. I know, I used to work for them.
I really don't have the longevity in my impellers like the sample in my hand from the old 60's 18 hp. Once replaced, even with the new OMC impeller......just like the one I put into a 9.9 last night......I expect it to fail in under 10 years time......I can almost guarantee it. Been "playing" with outboards as a business since I rebuilt my first Johnson in 1966.
 
Back
Top