Evinrude Fastwin 18 1965 Low Compression

[fishinless]

I have used this motor for several years with barely satisfactory results. I checked the compression and found 65 psi on top and 75 on bottom. Could this motor be rebuilt and how difficult for a Sat. mechanic and where should i start for parts if recommended?

 

[Daviet]

Re: Evinrude Fastwin 18 1965 Low Compression

What is the engine not doing? Is this a manual start or electric?
The compression is not all that bad if you are using a manual recoil starter.
You could try putting some oil in the cylinders to see if the compression will come up a little, if so , the rings could be the cause.
Maybe a head gasket could be leaking some compression.
How is the spark?

 

[fishinless]

Re: Evinrude Fastwin 18 1965 Low Compression

The motor acts like it is only running half throttle. Every now and then it speeds up a little. It will not put a small 14.5 alum boat on plane. I am checking compression with starter. Put new plugs in last year and haven't used much. I will try a little oil in cylinders to confirm rings.

 

[Rick.]

Re: Evinrude Fastwin 18 1965 Low Compression

Do a spark test to see if it's running on both cylinders. They run surprisingly smooth on just one but lack power. Sounds like what your experiencing. Best of luck. Rick.

 

[1946Zephyr]

Re: Evinrude Fastwin 18 1965 Low Compression

Pull the flywheel and check your coils out. If the insulation is cracked all to hell, then you need to replace them. This is common on these OMC's If you put new coils and plug wires in, this motor will amaze you. The 18's are actually about the best motor ever made and very reliable

 

[fishinless]

Re: Evinrude Fastwin 18 1965 Low Compression

I will check spark and coils-good advice.

 

[samo_ott]

Re: Evinrude Fastwin 18 1965 Low Compression

Sounds like ignition kicking in and out. I'd also do a decarb on it to see if you can bring up the compression #'s.

 

[fishinless]

Re: Evinrude Fastwin 18 1965 Low Compression

I started motor up in a can of water. I pulled off the top wire with plyers and the motor did not change speed or idle. I started to pull off bottom boot standing in water and quickly realized i had real good spark on bottom cylinder!! I pulled fly wheel and inspected. Coils look real good, points open as flywheel bolt is turned. Wires to plugs look new. One coil is red and one is blue?? should i replace all components while apart or is there an easy way to trouble shoot coils, condensors, and points?

 

[tx1961whaler]

Re: Evinrude Fastwin 18 1965 Low Compression

I just replace all of that stuff while I'm under there. It's usually good for about 20 years after doing that......

 

[Fuzzytbay]

Re: Evinrude Fastwin 18 1965 Low Compression

Visually inspect the face of the points for pitting, burns etc. The coils, replace em both, blue is old, the red ones even older. Coils are worth 25 bucks each at napa, and that is mot likely your problem. I run old motors, have always.......never could afford new. In all my years I have never replaced points yet. Condensers can fail, so check the lead wire, and the crimp on connection. Look for corrosion on the can itself. So if the points and condensor look good, just change out the coils. Take care mounting them, so they are flush with the face of the mounting boss's. Make sure you wire em up right and you should go flying in the boat then.

 

[fishinless]

Re: Evinrude Fastwin 18 1965 Low Compression

Thanks to both of ya. Have been very helpful. I will let you know when i take out the boat in a week or two after electrical repair. Hopefully fishinmore! Attempted to attach photo.

 

[14ftgrumman]

Re: Evinrude Fastwin 18 1965 Low Compression

Make that photo your avatatar.

That family of motors is the best that OMC ever built. Takes a lot to kill them and they sometimes thrive on neglect. What said above, but check the point gap, also. .020 each set. line up rubbing block with the highest part of the cam, and your're good to go.

 

[fishinless]

Re: Evinrude Fastwin 18 1965 Low Compression

New coils installed. Points and condensors look new-when plugs are pulled and grounded there is strong consistent spark. Motor decarbed with sea foam and carb taken apart, cleaned and inspected down to needle valves. Motor runs well at idle in can-after new coil. After carb cleaning and new plugs motor idled a little higher and low speed idle needle valve seemed to change motor idle like it should. My mix is 50 to 1 and using synthetic. 16 oz of syn to 6 gal gas. I took motor for a spin this morning. The motor started good, idled good, and slowly tried to get 14.5 alum boat with two people and two batteries on plane but failed to. Adjusted motor trim pin to three different settings but did not help. Motor ran smooth at full throttle but lacked power. Got home and rechecked compression and spark. Good spark in both. Compression better than when starting. 80 psi in both top and bottom. Help!

 

[Fuzzytbay]

Re: Evinrude Fastwin 18 1965 Low Compression

Depending on the weight of the boat, the batteries and the people, as well as the locations of the load, its possible the motor dosen't have enough power to get up on plane, no matter how the pins were set. Try it in the boat empty, then see how it goes.

 

[Rick.]

Re: Evinrude Fastwin 18 1965 Low Compression

Well I think it should plane nicely provided you don't have a ton of accessories in the boat with you. Sounds like your getting small improvements but not enough to enjoy this set up. Two more things come to mind. I wonder what your engine rpm is at full throttle. At full throttle check to see if your throttle plate is fully open. Do you think there is any chance of your prop being spun? (well that's 3) It is possible the prop will slip under load without giving you an obvious surge in rpm. Keep trying. That motor is an excellent match to a 14.5 aluminum (imo) Rick.

 

[fishinless]

Re: Evinrude Fastwin 18 1965 Low Compression

Good advice.....would the prop have to have a sheared pin or is there another way it could slip? I will look into both ideas.

 

[Fuzzytbay]

Re: Evinrude Fastwin 18 1965 Low Compression

The prop would slip, under load, however that would be the bite in the water slippage, not due to actual prop slipping on the shaft, shear pins either work or they....don't

 

[bonz_d]

Re: Evinrude Fastwin 18 1965 Low Compression

I too would suggest checking the throttle. On these tiller motors there are a number of nylon pieces and bushings in the throlle linkage that wear out. One is a pin for the control lever. I have replaced 4 of these on old motors in the past couple years. Cost about $4.00

I know it's really ard to tell but does the motor sound like it's coming up to full throttle when on the water?