Topic: 1968 18 hp evinrude – Antique Outboard Motor Club,Inc

This topic has 15 replies, 9 voices, and was last updated 9 years, 3 months ago by jerry-ahrens.

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March 22, 2016 at 9:19 pm #3897
coryttodd
Participant
I have a 1969 18 hp evinrude that seems to have loss of power. When I give it throttle in forward reverse or neutral with either the tiller or linkage on carb it bogs down. I took carburetor off and made sure it looked good and clean and still same problem. Can’t find any fuel leaks. Any suggestions on what it could be and how to fix it? Thank you.
March 22, 2016 at 10:58 pm #33802
cajuncook1
Participant
Cory, welcome to Aomci.

Lets get some basic information to begin.

– Is this motor new to you or have you had this motor for a while?

– If this is not a new motor to you, then has it run well prior to this?

– Have you done or had any recent work on this motor?

– how comfortable are you mechanically?

I know these seem like silly questions, but they some times reveal important information and help us to start you in the right direction. We want to use a systematic approach to rule out problems instead of changing this or replacing that and not truly figuring out what is the problem. Sometimes an apparent fuel problem can be an ignition problem.

Next questions will be if you have tested compression and spark.
March 22, 2016 at 11:02 pm #33803
lindy46
Participant
Could be many things. Try pumping the fuel line bulb when it bogs down and see if that helps. If it does, you could have a bad fuel pump. Have you checked compression? Have you checked for a strong spark on both cylinders? With a spark tester, it should jump a 1/4" gap.
March 23, 2016 at 12:01 am #33805
coryttodd
Participant
It was my grandfathers motor we used to use it all the time. He put it in shop to get it to stop shearing pins and got it out and never used it got sick and died. I got it when he died and it hasn’t ever ran since I got it. I had a several so called mechanics work on it and all they did was get it to crank and run in a barrel. And I’m some what knowledgeable about mechanics not good as you can tell on my next question. How do you test compression. The only way I know how to test spark is to take plug out and lay on block and pull rope and see if it sparks not sure if that’s the right way.
March 23, 2016 at 12:31 am #33808
fleetwin
Participant
US Member
Like everyone says, could be just about anything. Does the engine seem to idle OK in neutral and when put in gear? I’m just wondering if it is running on two cylinders….
How about trying this:
Close the choke slightly while the engine is bogging down during acceleration and see what happens. You have fuel delivery/carb problems if closing the choke slightly helps RPM pick up for a second. You might also try having an assistant pump the fuel tank primer bulb while the engine is bogging down to see if that helps out…
I’m "guessing" that the engine was put away with fuel in the carb after its last repair and that the bowl/high speed jet is plugged slightly. You mention having the carb off, did you remove the bowl? If so, was it dirty/green inside? Did you actually remove the high speed jet? It is threaded in behind the bowl drain plug. You really need a special screwdriver/tool to remove/install the fixed jet to avoid damage to the jet and bow.
Just remember the best advice is to start with the basic most simple tests, such as compression and spark, like everyone else has recommended….
March 23, 2016 at 12:47 am #33809
coryttodd
Participant
It sometimes jerks when at a idle. When I accelerate and close choke slightly it doesn’t change and or it dies sometimes. I did remove the bowl, the whole carburetor looks great like new and shiny no other color. I did not take high speed jet out because I didn’t have the tool.To get it to start I have to turn tiller as far as I can turn it, I just can’t put it in start position and hit the starter button to get it to start.( my grandfather had the starter put on so he could start it as he was handicaped). I don’t know if that matters I’m just trying to tell you all everything about it. And what is the right way to check compression and spark?
March 23, 2016 at 1:18 am #33811
fleetwin
Participant
US Member
Well, perhaps it is just running on one cylinder, the jerking you refer to might be the second cylinder kicking in for a second. When you advance the throttle, does the motor stall, or just keep running but low on power.
Have you tried new plugs? The spark should be able to jump a 1/4" gap while cranking. Sounds like the carb is clean, I’m glad you didn’t try to remove the jet without the tool…
Any way of posting a video of the engine running/misbehaving??
March 23, 2016 at 1:23 am #33812
coryttodd
Participant
It keeps running but low on power.yes I can post a video if you can tell me how to put it on here.
March 23, 2016 at 1:25 am #33813
beerman57
Participant
If it’s been sitting for a while, get a can of OMC Power Tune, Merc has one too I think and Valv-Tec (black label) is the same stuff. Disassemble carb and use the long, small tube to spray in ALL openings, rinse with a parts cleaner AND blow out all openings with compressed air. I would replace/rebuild the fuel pump too, after that little bit of maintenance you should be good to go. If not, you know it’s something else, but your fuel system is race ready!
March 23, 2016 at 1:59 am #33814
fleetwin
Participant
US Member
quote CoryTTodd:

It keeps running but low on power.yes I can post a video if you can tell me how to put it on here.

Posting here can be a pain…You can email the video to me and I will post it for you if you like…
Don
- This reply was modified 6 years, 8 months ago by fleetwin.
- This reply was modified 5 years, 7 months ago by seakaye12.
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