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Tan
Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 10662
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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On my 1992 Johnson 4 hp J4RENM a plastic bag caused the

Customer Question

On my 1992 Johnson 4 hp J4RENM a plastic bag caused the motor to overheat and warp the head. After installing a new head and gasket as well as an impeller the engine ran (and idled) well but no water squirted out of the 3 water pump indicator holes. I pushed a plastic wire tie up the holes 3 1/2' before any resistance was encountered. I removed the exhaust cover and lower end and attached a hose to the cooling water supply tube. Water freely flowed out of the channel surrounding the cylinder head but still none came out of the indicator holes. I taped over the cooling channels to help pressurize the system and still no water from the indicator holes. What is causing this and how can I fix it?
Submitted: 11 months ago.
Category: Boat
Expert:  Tan replied 11 months ago.
Hello. My name is***** the engine getting hot?When you had the cylinder head off did you inspect the water deflector # ***** in side the water passage?http://www.marineengine.com/parts/evinrude-johnson-parts-diagrams/JOHNSON/48267.gif
Customer: replied 11 months ago.
I did this job 10 years ago and then put the motor aside until recently. The motor seemed to run OK without overheating. I don't recall seeing the water deflector when I reassembled it. I can't tell where this is from the illustrated parts catalog.
Expert:  Tan replied 11 months ago.
Is the water pump 10 years old? If the pump is that old also you need to inspect the pump impeller as they will get hard and can break pieces of the impeller off. These pieces can get lodged in the motor.I can send you the link to the parts breakdown. http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1992&hp=4&model=J4RENM
Customer: replied 11 months ago.
Replacing the water pump is what I'm doing but before installing the kit I want to find out and fix the lack of water coming from the water pump indicator holes. What do I need to do now?
Expert:  Tan replied 11 months ago.
What kind of condition is the water impeller in that you are replacing now? I have to ask questions to determine what is causing your problem. This is diagnostics not guessing.If you want me to guess I can.These engine don't always pump water out through the exhaust outlets. Most of the water goes down out through the prop. The water exits out the exhaust ports when running at higher speeds.
Expert:  Tan replied 11 months ago.
If you got the engine hot enough it is a good possibility you melted the water tube grommet # ***** at the base of the power head. If the grommet is melted the engine will not get enough cooling water to the power head. This could be the problem.
Customer: replied 11 months ago.
The impeller was in good shape. There is wear on the #28 plate. When I forced water up the water tube I was getting flow out of the exhaust and down the shaft housing but no flow from the indicators.
Expert:  Tan replied 11 months ago.
These engine don't always pump water out through the exhaust outlets. Most of the water goes down out through the prop. The water exits out the exhaust ports when running at higher speeds. If water is coming out the exhaust housing then it is going through the engine.
Customer: replied 11 months ago.
Do I need to increase the water pressure going into the water tube to test the water indicators?
Expert:  Tan replied 11 months ago.
Those are not indicators but exhaust outlets. You can try that but as I stated these are not water indicators.
Expert:  Tan replied 11 months ago.
Let me ask you thins did you have the cylinder head checked and corrected for warpage?
Customer: replied 11 months ago.
I didn't. The motor ran well at speed but would not idle. Suspecting a warped head due to a plastic bag restricting water flow I installed a new head and the engine idled and ran fine. Only the water pump indicator was not flowing water.
Expert:  Tan replied 11 months ago.
Ok what you have to do to clear the water pump indicator is blow backwards through the indicator with compressed air. If you don't have compressed air follow the indicator hose to the engine pull the hose off the fitting and clear the fitting of debris this is where they clog.
Customer: replied 11 months ago.
There is no external water pump indicator hose. I have no shop air. Note that I was able to penetrate these 3 holes 3 1/2" where does the blockage occur?
Expert:  Tan replied 11 months ago.
At the water tube or in the engine block. When you had the cylinder head off did you inspect the water passages for blockage. If the engine got hot enough you probably melted the water tube grommet.
Customer: replied 11 months ago.
No blockage was visible. There seems to be plenty of flow down the exhaust housing. What number and diagram is the water tube grommet on?
Expert:  Tan replied 11 months ago.
It will be under midsection and the grommet is #10. Here is the link.If the grommet is bad the water doesn't go through the engine it will just dump in the exhaust housing. http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1992&hp=4&model=J4RENM&manufacturer=Johnson&section=Midsection
Customer: replied 11 months ago.
As I've tested the water flow with the exhaust cover off how could this be the problem?
Customer: replied 11 months ago.
If it is how do I get to it, install it and what parts will I need for reassembly?
Expert:  Tan replied 11 months ago.
If your getting water to the exhaust there is no problem. Is the engine over heating? Have you tested the engine temperature?
Customer: replied 11 months ago.
The motor does not appear to be overheating. Page 10 of the Operators Manual calls the 3 ports I have been referring to "water pump indicator" and if there is not a steady flow....see your dealer. So there does seem to be a problem. Please start over and tell me how to fix this problem.
Expert:  Tan replied 11 months ago.
Sorry can't help any furter. I don't have an answer. I don't know how you can have blockage in an engine that ran fine till you picked up a plastic bag. What got in the motor to block the water passages. I don't think you have a problem long as the engine is over heating there isn't an issue. Those are not water indicators but exhaust ports. They never put out much water. I don't know how I can be clearer. I have repeatedly told you those are not indicators. I will opt out as you don't want to believe there is no issue as the engine isn't over heating. Obviously it is getting enough water flow.
Customer: replied 11 months ago.
I didn't make the name up. It's what the manufacturer calls them. Let's just drop it.

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