Outboard cooling

[fisherman]

Just bought an old Evinrude 2 stroke, in nice condition, runs great, but low water flow. Came with a boat I wanted so not too worried. I tested it with the bottom of the leg, pump, prop in a tub, cordless drill on the drive shaft, showed the pump to be OK. Saved £50 for an overhaul kit. Problem was the rubber grommet on top of the pump too big for the copper pipe going up the leg, put a sleeve in it. But what I did find and didn't know: trying to get water out of the tell tale, the water actually falls out of the power head and dribbles down the inside of the leg (don't we all?), the pressure relief hole in the exhaust pipe blows the water towards and out of the four telltale holes. Bit random I thought. I suppose all these old engines were a bit basic.

 

[VicS]

You don't say what model. Hp and age.
The grommet at the top of the water tube causes problems with some. It becomes distorted by corrosion end eventually blocks the water flow. (Modified mine with O rings and nylon spacers.)

Older Evinrudes, and more recent small ones, did not have a telltale as such. You just had to look for a spray or mist from the backpressure relief ports. Larger models were designed so that a significant volume of water is blown out.

 

[stu9000]

Have you eyeballed the impeller?
Easy to do and while you've got some pumping going on it could be the impeller is disintegrating.

 

[andsarkit]

I recently acquired a Johnson 4HP 1992 which also has a very small flow from the 4 holes. It doesn't seem to overheat and I think it might be normal for these engines. I will change the impeller just in case as it may well be original.
They are nice little twin cylinder engines with a small internal tank and a fitting for an external tank for longer range.

 

[fisherman]

I believe it is a 4.5hp post 1981. Doesn't look that old. The local dealer showed me an old Johnson which is identical. He said too hot to touch (cyl head) is too hot. The impeller was the first thing I checked, it is good not perfect, only squashed vanes, and the test confirms a good flow, the drill only turns it slowly. The engine is worth little so didn't want to spend £50, but I will if I have to. There is £1 difference between the cost of a complete kit and just the impellor and gasket.
The lack of flow was caused first by the loose grommet/pipe interface, second by my sleeve inserted too far and obstructing flow at the bottom plate of the pump, so it all worked separately but not when assembled.
I was tempted for a moment to fix a short pipe into the outlet under the power head, for more clear flow indication. Copper/ally.......solder? Epoxy glue? Drill and tap?

Website suggests 1988. E5 RHCIC.

 

[andsarkit]

If you look for 'Evinrude Johnson Gale ID Chart' you should find a specification from the numbers on the plate.

 

[VicS]

I believe it is a 4.5hp post 1981. Doesn't look that old. The local dealer showed me an old Johnson which is identical. He said too hot to touch (cyl head) is too hot. The impeller was the first thing I checked, it is good not perfect, only squashed vanes, and the test confirms a good flow, the drill only turns it slowly. The engine is worth little so didn't want to spend £50, but I will if I have to. There is £1 difference between the cost of a complete kit and just the impellor and gasket.
The lack of flow was caused first by the loose grommet/pipe interface, second by my sleeve inserted too far and obstructing flow at the bottom plate of the pump, so it all worked separately but not when assembled.
I was tempted for a moment to fix a short pipe into the outlet under the power head, for more clear flow indication. Copper/ally.......solder? Epoxy glue? Drill and tap?

The model number will identify it. The 4.5 was produced from 1980 to 1987 but not sold in all markets after 1983

I would have replaced the pump impeller while it was accessible,. Especially if some of the vanes were distorted.

I would also have connected a hose to the bottom of the water tube to make sure there was an uninterrupted flow through the power head ( there is no thermostat)

ITYWF it is one of the models which has the troublesome grommet at the top of the water tube. Unfortunately you have to remove the power head to access it.

You should be able to touch and maintain brief contact with any part of the powerhead except the cylinder head and the exhaust manifold cover plate but if you have water droplets being blown from the relief ports and no steam it will be OK. If you see stem then it is overheating.

Check the condition of the gear oil. It should always be "clear and bright". Any milkiness is a sign of water getting into it.

5RHCS-5RHLCS	4.5	1980
5RCS-5RLCS	4.5	1980
5BACS-5BALCS	4.5	1980
5RHCI-5RHLCI	4.5	1981
5RCI-5RLCI	4.5	1981
5RHCN-5RHLCN	4.5	1982
5RCN-5RLCN	4.5	1982
5RHCT-5RHLCT	4.5	1983
5RCT-5RLCT	4.5	1983
5RHCR	4.5	1984
5RHCO	4.5	1985
5RHCD	4.5	1986
5RHCU	4.5	1987

 

[fisherman]

Thanks VicS. I put a pressure washer up the copper tube at first, all clear.
Yes I removed the power head to check for blocked waterways, there is a half round grommet in the plate at the top of the water inlet tube.
Must have had the bottom leg off ten times or more.
I kept trying it not realising it was my lower grommet rectification sleeve that caused the final obstruction, when I put the bottom of the leg on, but showed clear flow otherwise. I cut a bit off it and all OK. I was about to run the power head without the leg but with a drill on the shaft to drive the pump separately, hose between pump and copper pipe, but it was a bit difficult to set it all up.....