Evenrude 25 hard start/flooding after sitting.

The engine from this thread. https://www.tinboats.net/forum/viewtopic.php?f=4&t=43933


Figured Id start a new topic here for views.


After being run on the stand and being left to rest for a bit I think the motor is flooding out. Its east to pull over if I run it, shut it off and restart right away, but if I wait a half hour the first pull is easy then it gets ridiculously hard and I have to hit it with either or pull it 10-15 times.


Theres also a starting issue if I try to pump the bulb until it gets hard. If I pump it until I hear gas in the carb It starts in a few pulls but if I pump it more it floods.

Am I correct thinking both of these issues are float level/float needle related?

Probably has a film, deposit on the needle/seat. Needs a good cleaning. You may have to take a q-tip and spray carb cleaner on it and then really clean the seat good when you clean the carb. I have no idea what that film is but it gets on there and they will not seat.

If you buy an OEM kit which is best this will come with it.

Catfisher, which part of the state are you. I may have to bring a motor over there.

water bouy said:

Catfisher, which part of the state are you. I may have to bring a motor over there.

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Outside of Lexington, you have picked a bad time though. Fishing is wide open now and hunting is ramping up. I am semi-retired and only mess with stuff in my spare time.

No problem. I'm still getting the boat fixed up so I might check back when it turns cold. Or yell if you ever travel to Greensboro. I'm semi-retired from the electrical trade.

nccatfisher said:

Probably has a film, deposit on the needle/seat. Needs a good cleaning. You may have to take a q-tip and spray carb cleaner on it and then really clean the seat good when you clean the carb. I have no idea what that film is but it gets on there and they will not seat.

If you buy an OEM kit which is best this will come with it.

Click to expand...

I was looking at the Sierra kit that comes with the float.


I have the transom out of the boat right now and Im wondering if I should take this out for a short test run before I go all in on replacing parts after the transom if replaced.

I would hate to do the head and carb only to find out I have a bad lower unit or a cooling issue.


Or maybe its just me wanting to get the boat/motor out on the water.

I didn't realize that the motor wasn't proven. I can't answer that one for you. I mean are you going to junk it if it has other issues, or you going to continue to go through it and make it reliable?

As to the kit. The OEM kit has much more stuff like welch plugs and the small lead shot that goes in the ports to completely disassemble the carb and thoroughly clean it. If you don't have a float issue then it isn't necessary to replace it. Quite frankly from what I saw in the short vid I don't think you do but I could be wrong. That is your call. It ran pretty decent, probably a cursory cleaning will solve your problems but I am the type once I go to the trouble to take a carb off I want to thoroughly clean it.

I think pappy hit on it as I dont see fuel, I hear it.

I found a cl add for guide boards which when I went to buy them found them at a local marine service.

The owner told me the same as pappy about the primer and pump so Ill look there, but yeah I will go over the carb eventually.

As far as it being "proven", it was a saltwater motor which is the thing that worries me.

If i drain the lower and theirs no water, which having done the pump and looking at the oil on the shaft I dont think there is,it will be a runner.


If I put $150 on top of my $50 outlay and get a couple years out of it Id be happy. I just dont want to be constantly chasing issues.

One other thing.

By my measurement this motor measures 22" from the top of the clamp bracket notch (where it sits on the transom) to the cav plate.

The dealer said this should be 20" or 25", what gives?

It appears to be a long shaft in your vid.

My short shaft Merc 25 and Johnson 20 both measure 17" (2" more than the commonly referenced 15" short shaft).
Lots of motors are 2" over standard.

RaisedByWolves said:

One other thing.

By my measurement this motor measures 22" from the top of the clamp bracket notch (where it sits on the transom) to the cav plate.

The dealer said this should be 20" or 25", what gives?

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There are no engines that measure exactly 15" or 20". Same as transoms. None are exact. To further the confusion engine manufacturers vary the shaft length as well.
Yours is a long shaft which is universally recognized as a 20"
Want more confusion? OMC did make 22.5" engines for a while for the commercial market! Just thought I would throw that in there!

Pappy said:

Lets start with some basics.


A third check that needs to be made is the fuel pump itself. If the pump is mounted direct to the engine pull the pump off and squeeze the primer bulb. See if fuel comes out the port between the two mount screws. If it does then you need to invest in a rebuild kit for the pump.
It may also have a pulse hose that connects directly to the manifold on the engine. If so equipped then pull that hose and do the same test. If fuel flows from the hose you need a kit.

One of these checks should produce the source of your flooding if it is indeed flooding. Try these before just buying parts until you find the issue.

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OK, back at this.

I pulled the primer hose that goes into tiny barb fitting on the top of the carb, no fuel there.

Then I completely disassembled the pump and this is where Im confused. Your part in bold above has me stumped. If fuel didnt come out of the oval port in the one half of the pump body, how would it get to the carb?

The Diaphragm didnt have any holes in it, though it looked a little stretched as you would expect from an old diaphragm, and the two little "mushroom" looking things (Check valves?)covering the circle of little holes were not hard that I could tell.


Im thinking now maybe you meant the atmosphere hole in the bottom of the pump? The one that lets air go in and out of the back of the diaphragm.

I would put it on the water and run the piss out of it before diving in too far. And, like you said, you'll then know the overall condition of the motor.

When they sit, the gasoline evaporates, leaving a sticky oil film on everything. It takes some loaded run time to clear it all out. Fast idle in the barrel doesn't do much but load it up worse.

Adding a strong does of seafoam to the tank can help as well. I don't generally use it but it's inexpensive and can't hurt.

Put new plugs in too if you haven't, make sure they're gapped correctly.

Pappy said:

Well...I clearly stated the hole between the two mount screws. This is the pulse port.
If the pump has a third hose then it has a pulse hose on it and you were to pull that hose and squeeze the bulb to check.

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Gee, Um, thanks?

I did everything that you recommended and was simply looking for clarification on some details as it is still flooding. And yes, it is indeed flooding, no mistaking a flooded 2 smoke engine.

Sorry to have troubled you.

Is it hard starting or flooding? Some use flooding as a generic term for when they can't get an engine started. They probably choke and pull a lot of fuel thru it. What is flooded and where is the extra gas?
Choke gets used on ice cold motors on cold days and maybe for a few seconds as needed to build some rpm. If my motors don't start that easy I richen up the low speed. Most set low speed when it's running and if you get it just right they start with very minimal use of choke. One trick on hard starting motors is to just pull it easy once or twice to pull fresh air in. Third firm pull lights it right up. Ever see a tiny kid start big dirt bike? 3-5 easy kicks right after another is all it takes them. You say "flooded" so unless you misunderstood the troubleshooting for flooding you have hard starting. What is yours doing?