1973 9.5 Evinrude power/RPM issue

[bruisedreed]

Looking for a little direction from the 9.5 gurus here. I have done a lot of work on this motor and am really not getting anywhere. When I got it I took it out for a test run. Everything was good with it but it had very little power. I set the gap on points and put new plugs in and set the gap on them as well. Checked compression and found it to be a little low @ 65psi on both cylinders but not out of spec for this motor as I understand it. Motor ran smoothly but really didn't push my 14' jon boat like I would expect. I started working on it to do some maintenance since I didn't know much history on the motor. Replaced the water pump impeller (which was working fine just wanted to do it so I knew it had been done), which lead to tearing down to the power head to replace the water tube (someone neglected to use the retainer ring last time), which lead to other things including linkage repair (long story) etc. Also did a carb kit while I had everything apart soaked the body in acetone, blew out with air and then blew carb cleaner through everything for good measure. There was no debris and no fouling really that I could see to begin with. Looked as though it may have been serviced in recent history or just used very little. Everything went back together and seemed to be in order. Took it to the lake yesterday and started it (first pull). Put in gear and accelerates but only revs enough to move me forward barely above trolling speed. The throttle plate is fully advanced to fast position. I also attempted turn the mixture linkage (fully seated then back off 1 1/2 turns to start at the time of rebuild) with no noticeable difference. My initial thought was that it was running on one cylinder so I pulled plug wires one at a time and I can confidently say that it is firing both. Just no power. No change with the hood on or off, nothing I do seems to make it run badly either. It idles fine...very smooth, starts easily. Really just looking for some direction here with the most bang for my buck as far as what I try. I would rather not use the hunt and peck method for replacing likely culprits. I really don't want to sink money into it at this point and I'm kind of scratching my head.

 

[Crosbyman]

I have or.. had a similar issue with my 9.5 which is going to be retested in a few days

compression 65-70 good points coils carb cleaned etc.…….

but at full FAST I noticed the throttle plate as about 45 degrees open vs full open

make certain you adjust the linkage ok see picture

that slow speed needle is for idling

the main HS jet is inside and behind the lower carb bolt

 

[bruisedreed]

I have or.. had a similar issue with my 9.5 which is going to be retested in a few days

compression 65-70 good points coils carb cleaned etc.…….

but at full FAST I noticed the throttle plate as about 45 degrees open vs full open

make certain you adjust the linkage ok see picture

that slow speed needle is for idling

the main HS jet is inside and behind the lower carb bolt

That's at least a possibility. I will see what that does. let me know how you make out with your fix. I am a little unsure where the marks are and how to line them up. I will play with it a bit. Thanks for the pic and suggestion!

 

[Crosbyman]

the rolling nylon is set on the small step as per picture

loosen the screw and the trholttle plate in the carb should be shut


I had a bit of a problem to get a full on open throttle plate on FAST so try a few position

not sure this will solve my problem but I did not feel good with the throttle plate sitting at 45 degrees on FAST

 

[racerone]

Sounds like it is running on one cylinder.----Do this test.----Force the magneto to jump a gap of 5/16" on a test device.----Plug wires are known to crack / leak at the 90 degree bend coming down from the magneto plate.---Fuel pump diaphragm checked ?

 

[bruisedreed]

Sounds like it is running on one cylinder.----Do this test.----Force the magneto to jump a gap of 5/16" on a test device.----Plug wires are known to crack / leak at the 90 degree bend coming down from the magneto plate.---Fuel pump diaphragm checked ?

wires are new and dont to be leaking anywhere and the Magneto seems to give me plenty of spark I can jump a good long gap easily. coils are actually fairly new to definitely not original. They're both in good shape with no visible cracks or anything like that

 

[racerone]

Clean the carburetor.-----Is high speed jet in the bottom of the float bowl clean , yes or no ?

 

[Crosbyman]

there is a small hoe in the corner at the bottom of the float chamber which lets fuel reach the HS jet area.. make certain all passages are clear and open

a recent new to me 9.5 of mine had accumulated so much crud in the carb bowl and HS jet areas it was almost solid
calcium like deposit which needed to be "pick'd:fencing:" out

 

[bruisedreed]

Clean the carburetor.-----Is high speed jet in the bottom of the float bowl clean , yes or no ?

I am going to take the carb apart again and look closely. The whole carb and jet was really nice and clean. I am going to try again and make sure. I would think anything I couldnt see would have been cleaned up in the acetone bath

 

[bruisedreed]

there is a small hoe in the corner at the bottom of the float chamber which lets fuel reach the HS jet area.. make certain all passages are clear and open

a recent new to me 9.5 of mine had accumulated so much crud in the carb bowl and HS jet areas it was almost solid
calcium like deposit which needed to be "pick'd:fencing:" out

yeah I blew all that out with air then soaked un acetone THEN sprayed out with carb cleaner again. Everything looked clean and open to me

 

[Crosbyman]

blow carb cleaner directly on the HS jet orifice and make certain it come s out he main fuel
pillar tube wear eye protection !! protect tinted glasses from the carb spray

go to utube ask for the 9.5 carb cleaning video parts 1 and part 2

check with cajuncook on aomci he may provide you with his good 9.5 servicing PDF file

 

[dfrants]

spun hub? that happened to mine...

 

[bruisedreed]

spun hub? that happened to mine...

this motor has a pin drive prop no hub. Although I did have to replace the prop shear pin but thats another story. I think Im gettimg closer. did some linkeage adjustment and another high speed nozzle cleaning. seems better. A lake test is in order so hopefully I should be able to do that early next week.

 

[F_R]

this motor has a pin drive prop no hub. Although I did have to replace the prop shear pin but thats another story. I think Im gettimg closer. did some linkeage adjustment and another high speed nozzle cleaning. seems better. A lake test is in order so hopefully I should be able to do that early next week.

No hub??? Wanna bet?

 

[racerone]

It sure does have a rubber hub in the propeller.-----The novice does not accept that fact because you can not see it.----I say it is running on 1 cylinder or the high speed jet is plugged.----Perhaps parts missing that open the carburetor all the way ?-------Or perhaps the fuel pump has a tear in the diaphragm.----Should be an easy fix.

 

[bruisedreed]

I stand corrected. forgive my gaff...The hub is not spun. it is a new prop. Definitly firing both cylinders (runs poorly when you pull one and smooth with both.) Good strong spark. I just cant get this thing straight. I am really sick of tinkering with it. I will get it sooner or later I guess but It is frustrating. Everything appears right and I have cleaned/replaced everything that should make it sing that I can think of.

 

[thatone123]

So does that rubber hub slip like a thru-hub or just shear the pin?

 

[racerone]

123--- I am surprized by that question from you.-----They came with a stainless DRIVE PIN from the factory.----Not supposed to shear.-----The rubber hub is supposed to give / slip .-----But folks do not want the inconvenience of having to change a 29 cent shear pin.----Folks today accept having to buy a new prop.

 

[thatone123]

No R1 I did not know that it had a non-shear pin. That increases my admiration of that outboard as I thought it had a shear pin and I go shallow a lot. Maybe I will use it more often now.

 

[racerone]

You can use a brass shear pin if you carry a spare and know how to change it.----Save the steel pin for the last one.