Water seems to not be flowing. 1964 28 HP Evinrude Speeditwin 28402M

[Chris Koure]

I have a couple questions.

Is there a thermostat on my 28 HP Speeditwin?

I replaced my lower leg from a donated engine. I replaced the impeller and water pump housing grommet and greased the impeller. Both this engine and lower leg is new to me.

I’ll be pulling the lower leg again and probably the upper leg too looking for a blockage. The water tube is clear but installs from the bottom and I’m 90% sure it should be installed from the top of the upper leg. The replacement water tube I purchased is longer and bell mouthed at the top.

I’ve only run this engine in a bucket for less than 30 seconds at a time. The engine came from a friend (without the lower leg) and it ran and pumped water fine.

I made a duct tape cup for the water exit and I see nothing. Attached picture is of my setup.

Thank you everyone for reading my question.

Chris

[Phil Budne]

I’m 99.44% sure your 28 is a reincarnation of the 1950’s 30 (as the 33 is the reincarnation of the 35), and doesn’t have a thermostat.  Here’s the parts diagram of the power head:

https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1964&hp=28&model=28403M&manufacturer=Evinrude&section=POWERHEAD+GROUP

The thermostat would be at the top of the cylinder head.

http://www.omc-boats.org
http://www.aerocraft-boats.org

[Chris Koure]

Thank you Phil,

I’m going to do what I can to get the leg submerged more. Water is above the horizontal holes on the leg. I was searching the same exploded view drawing looking for a thermostat. I believe I have a 1957-8 carburetor on it so I agree I believe most parts transfer from the earlier 30 HP. One question about the water tube. (Not that I expect it to be common knowledge) I’m thinking I should install the water tube through the top of the Exhaust Housing Assembly? I’m not sure how the 30’s went together. It looked like the top of the tube was cut to allow install from the bottom. During assembly the water tube went into a hole more than 1½” but I’m uneasy because that engine was cooked. Pic is of my new old stock water tube and the one I used. I’m ordering that plate gasket so I can do that!

[fleetwin]

OK, no thermostat on these engines.   Is there any spray at all coming from the relief hole?  I don’t really understand what you are referring to about the water tubes.   You bought the engine with no gearcase, does the powerhead look like it has been overheated in the past?

[labrador-guy]

Chris, there is not enough water in your bucket.   Water needs up and over the bulge where the impeller sets.  Check that before you tear it back apart.

dale

[bob-d]

Having chased poor water flow on my 64  28HP I would like to offer a few suggestions.
First there is absolutely no thermostat.
Drop the lower unit, hook a hose directly to the pick up tube and run it to see if it runs and stays cool.
If that works next check your lower unit. Look under the plate where the impeller is. The metal webbing is know to crack, as the water in this specific year motor does not drain properly, and can freeze over the winter. This causes cavitation and poor circulation going to the head. This was the problem I had. I was lucky to find a replacement lower unit, but if you can’t you can try rebuilding it with some JB Weld.
If you look up 28HP overheating issues on this forum you will see my thread.   I drove Don ( Fleetwin) and Frank crazy for months trying to figure my overheating problem out. Frank finally came up with the solution having seen the webbing crack on a few motors he worked on.
Hope this helps.
Bob D

[Chris Koure]

Thanks Bob D,

I’m going to be looking where your pointing. I have 3 28HP Speeditwins and 1 28HP Johnson(all 1961-1964). I only have 3 lower legs. The only lower leg that wasn’t cracked is the one I’m working with and that one came from the cooked Speeditwin! I might get 2 good ones at some point but, I must learn all their faults and weak points first. The Johnson 28, I’ll be pulling that leg next week and I’ll look very close at that impeller/plate area. Because you are one of the two people I know that have had a 61-64 28 HP lower leg off do you know if that water tube “must” be installed from the top of the exhaust housing assembly?? (See my pic of water tubes.)

Thanks again, I appreciate you sharing your first hand knowledge,

Chris

[bob-d]

Chris, the tube should remain hooked to the powerhead when you remove the gear case. Then just hook up a hose and shoot water up into it, which will rule out any water blockage. You can also start and run it, with that configuration.
Bob D

[Chris Koure]

Thanks again Bob D,

Your saying the water tube should stay attached when the leg is pulled speaks volumes. (See my water tube Pic, I’m using the short one) The lower leg I’m using was perhaps the reason the parts engine got cooked.  I will do the hose on water trick you suggest but first I’ve got to replace the water tube. I need to pull the mid/ upper/ exhaust housing. I also agree that something “must” be wrong with my impeller area (new impeller) perhaps the plate, but I’ll get open for to closer inspection. Once it’s back together I’ll be sure to submerged it more somehow.

Thanks again, again and again,

Kids coming over on Sunday and a Safe Boat Exam on Friday so I’ll be studying and honey-doing for a couple days. Tuesday I’ll be to camp pulling another leg from the Johnson 28 parts motor.

[bob-d]

Chris, in order to replace the water tube you will have to pull the power head. This is what it looks like once the power head, and lower motor pan are off. You can then drop the tube down, and the flange will hold it in place? I have never replaced a water pickup tube. Possibly another member can shed some light on how to secure ?  Once the tube is in position  the bottom of it pushes into the rubber grommet on top of the water pump.
Bob D

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