71 Evinrude 18HP not running well...sometimes not at all...

[judsondeancole]

I synchronized my linkage and cleaned the carb. I tore apart the fuel pump and rebuilt it. I bought a new gas tank and supply line and put on new plugs.....what else. I got it started after it sat for about 3 years. It ran rough, but it ran. It quickly died on me and I diagnosed some easy fix problems. I finally got it running pretty smooth and have taken it out about a dozen times. The only problem I had was a hard start on a cold morning. I took it out last Sunday to do some fishing and it wouldn't start. After 2 hours it finally cranked and ran well.......then it died #-o . I tried to start it and it acted like it was not getting enough fuel, it would die out after I let off the throttle. I cranked, and I cranked, and I cranked to no avail [-o< . I finally broke the starter pawl. I just don't know what the problem is. Also, I bought another starter pawl but I'm unsure of the exact replacement procedure. I think it is on right, but I took the return coil assembly off and have not put t back on the boat to see if it is operational. Any advice would help with getting my motor runnin and any advice, diagrams, or schematic of how the starter pawl and spring need to be orientated woul also greatly help.

Thanks..........

 

[Jim]

:WELCOME:

Thanks for joining. How does the spark plug look?

 

[sccamper]

Welcome to the board.

I might not be able to help you fix it but I can tell you that you are not alone. Ive got a 72 20hp johnson. I cant tell you how many blisters Ive had from pulling that rope. I first rebuilt the fuel pump but then replaced it on the advice of a boat tech. I have also noticed that the more I used the boat the better it ran and became more reliable. Also, make sure you have good FRESH gas. That one got me after having to replace the broken crank. Might have been 3 months between the trip the crank broke and repair.

 

[Ouachita]

You can look at the schematic on this site. Just have your model # ready.
https://tinyurl.com/5obqhs

 

[Quackrstackr]

Some motors are just cold collared. My brand new 90hp Merc. is one of them.

I took it out in 30 degree temps over the weekend and was wondering if I was going to get it cranked and warmed up before killing a battery or a starter.

Any trace of water in the fuel is going to cause you serious problems when it gets cold. This wonderful ethanol mix gasoline that we all get now is notorious for absorbing moisture in a very short amount of time.

 

[bassboy1]

I am led to believe you still have a fuel delivery issue, since the you also had a problem with it dying after having run for a while. Most don't like cold starts (especially mercs, from all vintages - no this isn't one of my jokes neither), but you shouldn't have any problem again after it has been warmed up, and ran.

When was the last time the carbs were cleaned?

 

[judsondeancole]

Thanks ya'll for all the responses. Now to answer a few of your questions:

Both of the spark plugs are new and upon further inspection they are clean and dry...

I cleaned the carb about a month ago and have had the motor up and running like a champ with it cleaned and rebuilt, so...

And the gas is somewhat fresh...a week old....i would consider that still pretty fresh.

Today I did replace the spark plug boots because the old ones were wearing thin and had exposed the metal coil in the boot. I don't think this is where my problem lies, but I changed them to prevent any issues down the road. I also got my new starter pawl replaced correctly. I just have to wait until the weekend to go try it out.

One last note............I had a friend tell me a possible problem I might be having but thought I would run it on here to see what ya'll thought. He told me that I need to crack the vent cap on my plastic gas tank or the engine will "vapor lock". It sounds logical but I was unsure if this could be my problem.

Let me know what ya'll think................................

 

[ACarbone624]

I would say you need to open the vent on the tank to keep the fuel moving.

 

[captclay]

When you cleaned the carbs if you did not replace the needle and seat they could be sticking,causing a problem too.also might check the plug wires with an ohm meter to make sure they are not breaking down.

 

[bassboy1]

One last note............I had a friend tell me a possible problem I might be having but thought I would run it on here to see what ya'll thought. He told me that I need to crack the vent cap on my plastic gas tank or the engine will "vapor lock".

Yep, that needs to be open. Shouldn't do much on a cold start though, but that could just be a cranky engine (I have one that is very reliable, but is a real b****y little thing. I can count on it to get me where I need to go, but it never fails to make me look like a fool at the ramp - must be female).

 

[judsondeancole]

captclay....i did not replace the needle and seat, but again I have had it running since I have cleaned the carb and running very well.

I think maybe it is just a cantankerous at cold cranking.

I will try opening the vent on the gas tank and avoid the vapor lock and if think hard enough....i want to say that the vent was cracked on the same tank when i had the motor running smoothly. I bought the tank, filled it with mixed gas, hooked it up, and away i went. I didn't pay attention to the vent until a couple weeks ago when my troubles started.........maybe it's as simple as that.......MAYBE............

thanks again ya'll for helping to keep me sane..........i was cracking up over a little motor......

 

[Quackrstackr]

Most definitely open that vent. Outboards don't like to run when you pull a vacuum on your gas tank.

 

[judsondeancole]

I took off early from work today and took the boat to the ramp to test it out....i'll be damned if it didin't fire right up.... #-o

I opened the vent on my gas tank and pulled 3 times and she cranked over. The weather is not as cold today, 63deg., as it was last weekend, but that is the smoothest start up I have ever had. So I backed it off the trailer and took it out for a run.....and run it did..........

Thanks to all who gave advice...

Now does anyone know just how fast this particular motor is supposed to run......

 

[Zum]

I didn't think 63 was cold,isn't that summer

 

[judsondeancole]

I didn't think 63 was cold,isn't that summer

that's winter time weather here............ 8) i love it.......

 

[sccamper]

My 72 20hp johnson pushes my 1436 flat bottom 17mph down hill with the wind to my back.