1970 25hp Evinrude runs for 30 seconds, dies, wont start

zacharyb · Jan 20, 2013

hey all,

A couple of months ago I purchased a 1970 25hp Evinrude 20052e for $150. The guy said the carb and fuel pump were replaced in August, but I have my doubts. Since purchasing it I have rebuilt the carbs, replaced points and condensers.

This week I put it in my barrel to see how it would run with the new improvements. It started right up and only ran for 30 seconds and then was unable to start back up. After waiting a day I lifted the gas tank up a foot above the motor and tried again, a couple of pulls and the motor started right up with choke on. Over about 30 seconds I eased the choke off and let it run for another 30 seconds, then it died. I pulled out the plugs to do a spark test and seem to have good spark on both cylinders. However the top cylinder plug looks like:

And the bottom:

I am running with new fuel and thought it might be the fuel pump. My plan for the future is to move my gas tank to the front of my 14' boat, so I was planning on rebuilding the fuel pump anyways. However, now that I pulled the plugs out and saw that one was fowled and the other fine I am not sure what to think.

After putting the motor up on my stand I went to drain the lower end oil and only water came out. The hole in front of fill plug was draining black fluid.. any suggestions there?

jasper60103 · Jan 20, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

Zach,
welcome aboard. Sounds like you got a couple issues with your motor.

When a plug looks clean like that usually means water is getting in the cylinder. Also, the motor won't run right either. Start with a compression test and post your numbers back here.

The gear case is getting water too as you discovered. You can try replacing the drain/fill washers and see if that fixes it. Else, the gear case will have to be resealed.

zacharyb · Jan 20, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

jasper60103 said:
Zach,
welcome aboard. Sounds like you got a couple issues with your motor.

When a plug looks clean like that usually means water is getting in the cylinder. Also, the motor won't run right either. Start with a compression test and post your numbers back here.

The gear case is getting water too as you discovered. You can try replacing the drain/fill washers and see if that fixes it. Else, the gear case will have to be resealed.

Thanks for the info. I did a compression test with a Harbor Freight tester and both cylinders come out to 70. I wish it were higher, but I was happy they were the same.

Do you think the water in lower cylinder is from a leaking exhaust gasket, or could it be related to the lower end water?

JB · Jan 20, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

Hmmmmmm. What happens after 30 seconds that wasn't true at start?

* The ignition parts may get hot enough for a part failure that works fine when cold. That dual magneto system usually doesn't lose both cylinders at once.

* The carb may use up the fuel it had at start and not be getting more.

I think it is running out of fuel. That could be anything from an unvented tank to a obstructed pickup to air leaks in the fuel lines to a failing fuel pump to a stuck inlet needle to the carb.

Your compression is passable and it wouldn't cause your symptoms if it wasn't. Forget that for now and check out your fuel supply system.

kodibass · Jan 21, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

Just to quickly rule out the fuel pump, it starts cold, so next time you start it pull the pump to carb hose for the 20 or so seconds after start up ans see if fuel-mix is pumping out.

bonz_d · Jan 21, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

I have to agree with JB and running out of fuel.

Not long ago I had an 18hp that did the same thing even after a carb rebuild. I finally found that the float needle valve was sticking and not openning. Doesn't take long for those small bowls to run out of fuel. So look there 1st and while it's apart check to make sure that when upside down the float is level and then turn it over and watch the needle valve under the float to make sure it's openning. Next, pull the cover off the fuel pump and check the screen inside that it is not blocked.

oldman570 · Jan 21, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

A serach on the web for LeeRoys Ramblings should get you alot of info that can be used on your 25. It is mainly for the 9.5 and 9.9 motors of that vintage and your 25 has alot of the same setup as those motors. The point settings and cleaning of them along with carb settings and lower and upper crankshaft seals all will have an effect on the motor. With a motor that old there are so many things that need to be checked that it can be hard to point out just one that could be causing trouble. Best to start at the top and check all the settings of every system. The fuel supply sysrem will need to be gone over and I would replace all the fuel hoses as time and the etheniol fuel used today can deterate the older hoses, and rubber in the fuel pump and carb, used in those motors. That motor was, and is, good runners when maintained correctly.
The LU will need a total reseal done if the washers for the vent and fill screws dose not keep the water out. JMO
Oldman570

zacharyb · Jan 21, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

Thanks for all the replies, I appreciate all of your help. It sounds like the fuel system could be causing some issues, what do you all think about jasper60103's suggestion of water in the lower cylinder?

jasper60103 · Jan 21, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

zacharyb said:
Thanks for all the replies, I appreciate all of your help. It sounds like the fuel system could be causing some issues, what do you all think about jasper60103's suggestion of water in the lower cylinder?

Zach,
proceed with advice given on the fuel system. Also, you can swap the plugs and see what happens. Good luck.

zacharyb · Jan 21, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

Tonight I was able to get the carb back off, the needle is not sticking. The fuel filter is not clogged and neither are either of the hoses going from filter. Tomorrow I will try to remove the hose from pump to carb while running and let you all know what happens.

zacharyb · Jan 22, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

kodibass said:
Just to quickly rule out the fuel pump, it starts cold, so next time you start it pull the pump to carb hose for the 20 or so seconds after start up ans see if fuel-mix is pumping out.

Alright, did this test and fuel came out of the pump in a constant stream at high rpm and in spurts while idling.

Jasper brought up water in one cylinder causing one plug to be clean and the other to be dirty. So even though I know it isnt good, I ran the motor without water to see if it would run longer than 30 seconds and it did. Could the problem Jasper brought up be the cause of my problems?

zacharyb · Jan 22, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

I am going to get a new impeller now

nwcove · Jan 22, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

just curious, but unless you think you cooked the impeller, why replace it before you find the real issue?

zacharyb · Jan 22, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

i just wanted to mention that so me starting it without water wouldnt become the main focus

jasper60103 · Jan 23, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

zacharyb said:
Alright, did this test and fuel came out of the pump in a constant stream at high rpm and in spurts while idling.

Jasper brought up water in one cylinder causing one plug to be clean and the other to be dirty. So even though I know it isnt good, I ran the motor without water to see if it would run longer than 30 seconds and it did. Could the problem Jasper brought up be the cause of my problems?

I mentioned it because I'm dealing with this issue on one of my motors. The exhaust cover gaskets aren't that expensive. Don't run your motor too much if you suspect water is getting in the cylinder.

zacharyb · Jan 23, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

jasper60103 said:
I mentioned it because I'm dealing with this issue on one of my motors. The exhaust cover gaskets aren't that expensive. Don't run your motor too much if you suspect water is getting in the cylinder.

After making a special tool to get down between the motor housing and exhaust cover I was able to remove the cover. I found a small trace of water along the bottom of both gaskets, so maybe that is what is wrong. I am placing an order for a lower end seal kit and new exhaust gaskets now so hopefully I can install them this weekend and give it a shot.

zacharyb · Mar 19, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

Hey all,

Sorry it has been so long. The weather here has been crazy and my workshop is in my uninsulated shed.. So I held off until last weekend.

Anywho.. I was able to get the exhaust gaskets replaced, new impeller, and resealed lower unit. I am going to try starting it up tonight and will post with any updates.

zacharyb · Mar 19, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

I want to start by thanking everyone who contributed to my issues. Today I was able to get the motor started on first pull and have it idle for 30 minutes in a bucket until I killed it.

All of my problems are fixed and I'm ready to get out on the water! Thank you all so much, it's so great to have this resource at our finger tips!!

samo_ott · Mar 20, 2013

Re: 1970 25hp Evinrude runs for 30 seconds, dies, wont start

What a happy ending!

1970 25hp Evinrude runs for 30 seconds, dies, wont start

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