'67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

paulorr · Jul 13, 2013

Well, I have a 1967 Evinrude 5 HP outboard.

My electric trolling motor is faster.

I took it to a marina and they replaced the floats, plugs and regapped the points.

It is better, but does not push my 12' aluminum boat anywhere near the speed as similar on Youtube.

Motor starts rightup no problem. Idles real nice just plain slow. Like maybe 5 MPH tops.

What do you think might be wrong with it?

Paul

boobie · Jul 13, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

Is it running on both cylinders ??

paulorr · Jul 14, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

boobie said:
Is it running on both cylinders ??

Well I assume it is running on both cylinders because I just paid a marina $189 to rebuild the carb. They said the cork floats were crumbling from the new ethanol based gas. I went and bought all new ethanol free gas. They also replaced both plugs.

It runs faster now, but I know this motor should fly but it still is slow. Like maybe 5 mph at best.

I'll try testing for both cylinders firing. If one is not then would that be an electrical issue?

Paul

82rude · Jul 14, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

its also possible you have the wrong propeller for your application.

paulorr · Jul 14, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

82rude said:
its also possible you have the wrong propeller for your application.

Well marina said that's the right prop. They thought some bushing in the prop might be slipping but this model has no bushing and has a brass pin that locks down the prop to the shaft.

Paul

bbstacker1 · Jul 14, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

Weight distribution can be a big issue on that size motor and boat combination. If you haven't already, see if you can get weight more centered or towards the front of the boat. Many people use a tiller extension and sit on the middle seat.

82rude · Jul 14, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

paul ,does the prop have a rubber insert?if so yes it can be no good and slip .can you find another prop to at least try and rule out that part?

paulorr · Jul 14, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

I checked the engine for both cylinders running and both are definitely firing.

The prop does not have a rubber insert .... we checked for that too. The marina looked up the prop for that motor and said the prop is the right one for this engine.

I am running on a MirrorCraft 12' v-hull. It is not a deep v hull. But the motor is a short shaft. But the transom is not real high. IN fact probably oh maybe 8" off the water?

I do get a small wake off the back and I get probably 5 mph out of it.

I just don't get it I expected this thing to fly on this small of a boat.

Paul

boobie · Jul 14, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

How much weight do you have in the boat including yourself when you're running it ??

paulorr · Jul 14, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

Well, I weigh 185 lbs. The boat I have no idea.

I went to West Marine for unrelated reason and got to taking to the guys there. One said it probably needs more HP to get up on plane. He said it takes 3x the horsepower to get up on plane than to run. He said if I could get it up on plane it would probably fly. Of course they were out of tiller extenders.

But he said power comes from compression and I should get a compression test done. If it needs new rings = not worth it.

Paul

boobie · Jul 15, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

Is there any kind of horse power rating on the boat ??

nwcove · Jul 15, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

i can only assume that the op's boat is probably rated for 15hp or 11kw. expecting it to "fly" with a 5hp maybe asking to much. (a temporary tiller extension can easily be made from a piece of pvc pipe and a couple of hose clamps)

Cap'n Chaos · Jul 15, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

I have a 1965 6HP on a 12' Lowe aluminum boat, with 400# of bodies and gear mine will certainly move faster than a trolling motor.

Have you checked spark with an open air tester, checked compression?

Did they adjust the cam roller to synch up the timing and carb?

paulorr · Jul 15, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

hmm cam roller .... i'll call the marina and ask ......

Cap'n Chaos · Jul 15, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

That's worded all wrong... sorry for the confusion.

There is an arm on the carb with a roller on it, which rolls against a throttle cam on the armature plate. On my 65 you can adjust the cam by loosening a bolt and moving the cam outwards or inwards to adjust the point where the carb just begins to open with the timing marks on the throttle cam. This adjustment puts the timing and carb in synch...

On my 1972 the throttle cam is not adjustable, but the adjustments can be made on the carb itself.

paulorr · Jul 17, 2013

Re: '67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

Well the MirrorCraft site says take the boat's HP rating and take 2/3rds of that number and that is the minimum. It is hard to read but I think I see 15HP. 2/3 of this number is around 8 HP so the motor is a little too small for the boat.

I made a tiller extender out of a PVC pipe and sat in the middle seat and it goes much faster .. acceptable speed.

So that must be the issue ... plus I suspect a motor that old has a lot of ring wear so I am probably loosing some horsepower to lessening compression.

Many thanks guys and gals .

Paul

'67 Evinrude 5 HP is S-L-O-W ...... whats wrong with it?

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