18 hp evinrude fast twin 1968

rkaffana

Recruit
Joined
Aug 30, 2007
Messages
3
I recently aquired a 18 hp fast twin that was recently "tuned up"
I purchased a new gas tank & fuel hose, new gas (50:1) and started the motor.
it ran rough but it ran- next attempt on the boat, the motor started okay, idled rough,but smooth out under power. it had a tendency to surge somewhat at full throttle. 1 week later the next run was even better- it started easily,had a rough idle but ran well at full throttle and I was a happy camper.
1 week later, same tank of gas, it just barely started, idled very rough, and would not accelerate when opening the throttle, it would sputter and die. now, it won't start at all. it pulls easy when trying to start it, the thermostat did work on previous runs, there was no overheating and the total run times of all 4 runs was about 40 minutes.
the plugs are new, the filter screen on the fuel block is clean, the hoses all seem okay. the gas is okay.
does anybody have a few words of wisdom?
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: 18 hp evinrude fast twin 1968

Does "pulls easy" mean with no resistance, like in no compression? At any rate, the procedure at this point is start the troubleshooting at the beginning. Check compression. Check spark and plugs. I seriously doubt it is a fuel problem, but that is next.

Dare I make a wild a** guess? Whoever tuned it up didn't use a torque wrench to tighten the flywheel nut to proper specs and the key sheared.

Second guess is the motor has bad coils.

Let us know which it is.
 

rkaffana

Recruit
Joined
Aug 30, 2007
Messages
3
Re: 18 hp evinrude fast twin 1968

pulls easy or i should have said normal resistance. not seized. the thing that has me perplexed is the evolution of the way it ran, ok-good -better- puked!-won't start.
i have worked on cars but not outboards,so i am greatly perplexed with this set of "symptoms"
how can something that seems to get better with each run then reverse the trend?
i have been reading many postings and most of the guys seem to be real passionate about the older motors and some guys really know their stuff. Me, i'm old, don't have a lot of free time and I'm looking for a quick fix. given those parameters, is this a motor for me? or should i try to sell it and go for something newer?
the intent was to get an aluminum boat (Done) and take the grandkids fishing.
at this point, i don't trust the motor. i live by the long island sound (NYside) and a goood wind could float me to Conn. if i have engine problems.
i have a 5hp tohatsu from a friend that pushes me around but i was hoping for a little more hp therefore, the 18 hp fastwin.
 

rkaffana

Recruit
Joined
Aug 30, 2007
Messages
3
Re: 18 hp evinrude fast twin 1968

pulls easy or i should have said normal resistance. not seized. the thing that has me perplexed is the evolution of the way it ran, ok-good -better- puked!-won't start.
i have worked on cars but not outboards,so i am greatly perplexed with this set of "symptoms"
how can something that seems to get better with each run then reverse the trend?
i have been reading many postings and most of the guys seem to be real passionate about the older motors and some guys really know their stuff. Me, i'm old, don't have a lot of free time and I'm looking for a quick fix. given those parameters, is this a motor for me? or should i try to sell it and go for something newer?
the intent was to get an aluminum boat (Done) and take the grandkids fishing.
at this point, i don't trust the motor. i live by the long island sound (NYside) and a goood wind could float me to Conn. if i have engine problems.
i have a 5hp tohatsu from a friend that pushes me around but i was hoping for a little more hp therefore, the 18 hp fastwin.
 
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