Evinrude 40hp 1998 vro. Starting and running trouble

[ohabu]

Hi everyone smarter than me!

I am currently working on the engine in the title, having received it as a non-runner. After testing electrical system I changed the power pack and got the spark as expected.

However it starts, then spits out the exhaust, then stops. I get it running at times, but then it is stuck at a set rpm (1500-2000 maybe) no matter what I do. This seems to me like a sensor problem of some kind. It has great cooling, and the oil tank is almost full. Instruments give me no warning of any kind.

- Spark plugs are almost new. Both shows spark but get very oily. I've ordered new ones for tomorrow.
- I use brand new fuel.

- There has been some water in the fuel tank according to the owner. He also experienced the rpm problem himself last year.

My gut tells me to tear open the carbs and the vro pump to clean out the water, also that the fuel pump might have some kind of a problem. However Evinrudes are really not my strongest suit, so if I'm missing something obvious I'd really love some tips.

Thanks in advance
- Jon

 

[ohabu]

Re: Evinrude 40hp 1998 vro. Starting and running trouble

To add something:
- When it runs, it feels like the stage of startup where the engine runs slow from a cold start even with tons of throttle applied. The few seconds before everything is fully fueled up and it roars into normal life and you quickly reduce the throttle.

 

[sutor623]

Re: Evinrude 40hp 1998 vro. Starting and running trouble

You are right on the money bud. I would replace the fuel lines, fuel pump/oil pump diaphram, and clean and reassemble the carbs (with new carb kits obviously). Water normally sets at the bottom of an oil tank, so you can just siphon the bottom of the oil tank. Or you could just remove the tank and give the tank a solid cleaning. All in all, I agree. Sounds like a blatent fuel delivery issue to me.

Wouldnt be a bad idea to put a new water pump impeller, thermostat, and lower unit oil either....

 

[ohabu]

Re: Evinrude 40hp 1998 vro. Starting and running trouble

You are right on the money bud. I would replace the fuel lines, fuel pump/oil pump diaphram, and clean and reassemble the carbs (with new carb kits obviously). Water normally sets at the bottom of an oil tank, so you can just siphon the bottom of the oil tank. Or you could just remove the tank and give the tank a solid cleaning. All in all, I agree. Sounds like a blatent fuel delivery issue to me.

Wouldnt be a bad idea to put a new water pump impeller, thermostat, and lower unit oil either....

Thanks for the help I also made a boring video of me trying to start it a ton of times if anyone is curious:

Halpmeh evi vro 40 - YouTube

 

[gm280]

Re: Evinrude 40hp 1998 vro. Starting and running trouble

I concur with sutor623's post. A great place to start and eliminate first... Could be all you will need to do to...

 

[ohabu]

Re: Evinrude 40hp 1998 vro. Starting and running trouble

Bumping my own thread. About to tear out (the remains of) my hair here

So after cleaning and rebuilding the carbs+vro everything was the same untill the engine lost spark again. Now I'm both confused and quite frustrated.

Could a failty stator ring have killed both my old and my brand new power pack? The engine runs like the timing is off - pretty good with no throttle applied but spits from exhaust whenever throttle is applied. I've measured the stator ring and both peakvolt and ohm values are good.

The owner has never touched the engine himself, so I don't suspect any weird mechanical diy causing problems.

To sum up:
- New power pack gave me back spark
- Rebuilding carbs and vro gave me back idle
- Anything above idle throttle makes the engine spit and die
- I lost spark again

Really need some help right about now

 

[ohabu]

Re: Evinrude 40hp 1998 vro. Starting and running trouble

Update on my last post:

I took the power pack off and reinstalled it again, this time getting a nice clear spark. Then after pushing the boat out, connecting the hose and the gas tank I lost it again. Clearly something is messing with me here. Could the rectifier interfere with the spark in any way?