68 9.5 rude just wont rev out.

[RaisedByWolves]

I worked on a coworkers family hand me down motor, carb kit/impeller and reseal of the lower unit.

Unfortunately after I worked on it, he worked on it........dont ask, hes a bonehead.


Anyway, the motor starts and idles fine, low speed running is great, but thats all that it will do.

It only pushes his 14' boat @ about 3mph.

The motor sounds good, but it just wont rev out and bring the boat up on plane.

Where would you start.

 

[Pappy]

Unfortunately after I worked on it, he worked on it........dont ask, hes a bonehead.

That sentence got me laughing!! Loved it.

Do your basics. I know you are capable then come back and relay what you find.

 

[CedarRiverScooter]

I would check the timing plate/carb linkage to see if the carb is opening up fully.

 

[Weldorthemagnificent]

Just how big a fella is he?

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[nccatfisher]

Just how big a fella is he?

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Now that one made me laugh.

 

[RaisedByWolves]

Lol, he’s a bean pole.

The throttle plate and throttle handle and rack all check out as far as I can tell.

He tried to grease the throttle shaft in the tiller handle not realizing there was a spring, and when he took the retaining screw out the handle took a moon shot down the driveway.

That is where I began working on it for the second time.

I had given it in addition to what is in the OP a new set of condensers but left the points alone save for a cleaning. Coils looked good and he said he checked for spark, but I’ll double check that anyway.

 

[CedarRiverScooter]

You can't check a coil by looking at it. You can check them with a ohmmeter. I forget the specification, but you can look that up. The coils in my motor looked fine but were bad when I checked them per the meter. It still had spark but wasn't strong. BTW don't buy Sierra coils, they don't fit right.

 

[nccatfisher]

You can't check a coil by looking at it. You can check them with a ohmmeter. I forget the specification, but you can look that up. The coils in my motor looked fine but were bad when I checked them per the meter. It still had spark but wasn't strong. BTW don't buy Sierra coils, they don't fit right.

And that right there was what I was talking about in another thread about Sierra coils just the other day.

 

[RaisedByWolves]

OK, still having issues after now replacing coils.

To recap, compression is good, Coils and condensers replaced and points cleaned, carb cleaned, new plugs, fresh gas, new prop.....

What am I missing?

What’s killing me is I can’t run the motor myself as it’s too short for my transom. I have to rely on captain boneheads stuttered explanation of what he thinks is happening.

 

[Pappy]

Okay....if you have done your work correctly then lets go to the next step.
That engine should have a high speed jet? Instead of an adjustable needle.
If so, tell me this.
When on the water and you nail the throttle does the engine accelerate normally then seem to back off?
If this is the case then look up the high speed jet size and purchase a new one. Yours may be worn out or someone may have tampered with it.
If this takes care of it then we will go into the reasons why this may have happened.

 

[RaisedByWolves]

That’s a thought.

A remote possibility, but then again his uncle who was my mentor during my apprenticeship had this motor last and did drink himself to death, so who knows what he might have done over the years.

I’m going to have to go out on the boat with him and see it running myself.

I don’t want to go out on the river with him, but at this point...

 

[Weldorthemagnificent]

Try it with the cover off. The exhaust rubber accordian thingy (yes, that's the technical term) are notorious on those motors. If it's leaking exhaust gas under the cover, it could be choking the motor on its own fumes.

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[MrGiggles]

I believe on those OMCs, the orifice for the main jet is in the bowl of the carb, not in the main body like most. There is a rubber donut gasket that seals the two together. If that is missing, it will idle all day but totally fall on it's face when revved. The plugs will be wet and it may flood out. Make sure it's there and in good shape.

 

[ClemsonAlum]

I have a '73 9.5 on a 14' jon too. Does 16 mph by myself with me (200 lbs) and about 150 lbs of stuff. 11 mph with 2 ppl.

Don't rule out a slipped prop hub too, those can fool ya. Bu it sounds like it is bogging down when you give it gas?

Yes, the high speed jet is in the carb body. Leeroys Ramblings has a ton of great info online.

Also check the Cork carb float to see if it is soaked up with fuel, and blocking the needle from seating and it turn flooding it or partially flooding. If the other things are not the culprit.

-Kurt
1436 PolarKraft & 9.5 Evinrude

 

[RaisedByWolves]

I believe on those OMCs, the orifice for the main jet is in the bowl of the carb, not in the main body like most. There is a rubber donut gasket that seals the two together. If that is missing, it will idle all day but totally fall on it's face when revved. The plugs will be wet and it may flood out. Make sure it's there and in good shape.

Im not seeing an o-ring on this diagram.

Pappy, I took it out and ran it solo and there was no bog, it just revved to a certain point and stayed there.

I added choke with no change. Well, it did die off a lil like it was going over rich but no change for the better.

I pumped the ball with no change.

Checked it was firing on both cylinders.

I did read on THT that there were some bad pump diaphragms from sierra so Im going to change that out and see if there is any change, but I would think that would have shown its self when I pumped the ball?

Stumped.

 

[RaisedByWolves]

Just went out to double check compression and it dont look good.


75 cold that bumped to over 90 with oil in the cylinder.

 

[Sinkingfast]

If yer been running 50/1 I'd run her on 20/1 for a tank full or so...betcha it might come back...done that on several so called worn motors and they all came back to life...but I still ran them at 20/1...assuming all systems are good..

 

[MrGiggles]

I believe on those OMCs, the orifice for the main jet is in the bowl of the carb, not in the main body like most. There is a rubber donut gasket that seals the two together. If that is missing, it will idle all day but totally fall on it's face when revved. The plugs will be wet and it may flood out. Make sure it's there and in good shape.

Im not seeing an o-ring on this diagram.

Pappy, I took it out and ran it solo and there was no bog, it just revved to a certain point and stayed there.

I added choke with no change. Well, it did die off a lil like it was going over rich but no change for the better.

I pumped the ball with no change.

Checked it was firing on both cylinders.

I did read on THT that there were some bad pump diaphragms from sierra so Im going to change that out and see if there is any change, but I would think that would have shown its self when I pumped the ball?

Stumped.

I checked the diagram for that carb, it does not use a rubber O-ring like the smaller motors, but is sealed with the bowl gasket.

When you cleaned the carb, did you remove the flathead screw and main jet from the carb bowl and clean them? #75, 76, and 77 in this diagram. They are often overlooked as it just appears to be a bowl drain, but isn't.

http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1968&hp=9.5&model=9823D&manufacturer=Evinrude&section=Carburetor+Group

 

[RaisedByWolves]

I believe on those OMCs, the orifice for the main jet is in the bowl of the carb, not in the main body like most. There is a rubber donut gasket that seals the two together. If that is missing, it will idle all day but totally fall on it's face when revved. The plugs will be wet and it may flood out. Make sure it's there and in good shape.

Im not seeing an o-ring on this diagram.

Pappy, I took it out and ran it solo and there was no bog, it just revved to a certain point and stayed there.

I added choke with no change. Well, it did die off a lil like it was going over rich but no change for the better.

I pumped the ball with no change.

Checked it was firing on both cylinders.

I did read on THT that there were some bad pump diaphragms from sierra so Im going to change that out and see if there is any change, but I would think that would have shown its self when I pumped the ball?

Stumped.

I checked the diagram for that carb, it does not use a rubber O-ring like the smaller motors, but is sealed with the bowl gasket.

When you cleaned the carb, did you remove the flathead screw and main jet from the carb bowl and clean them? #75, 76, and 77 in this diagram. They are often overlooked as it just appears to be a bowl drain, but isn't.

http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1968&hp=9.5&model=9823D&manufacturer=Evinrude&section=Carburetor+Group

Yep, went through the whole thing.

Im baffeled how it lost compression so quick, but it had sat for quite a while.

If it werent for it having lost compression I would be looking at case seals or something along those lines, but at this point, it is what it is.

 

[MrGiggles]

Im not seeing an o-ring on this diagram.

Pappy, I took it out and ran it solo and there was no bog, it just revved to a certain point and stayed there.

I added choke with no change. Well, it did die off a lil like it was going over rich but no change for the better.

I pumped the ball with no change.

Checked it was firing on both cylinders.

I did read on THT that there were some bad pump diaphragms from sierra so Im going to change that out and see if there is any change, but I would think that would have shown its self when I pumped the ball?

Stumped.

I checked the diagram for that carb, it does not use a rubber O-ring like the smaller motors, but is sealed with the bowl gasket.

When you cleaned the carb, did you remove the flathead screw and main jet from the carb bowl and clean them? #75, 76, and 77 in this diagram. They are often overlooked as it just appears to be a bowl drain, but isn't.

http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1968&hp=9.5&model=9823D&manufacturer=Evinrude&section=Carburetor+Group

Yep, went through the whole thing.

Im baffeled how it lost compression so quick, but it had sat for quite a while.

If it werent for it having lost compression I would be looking at case seals or something along those lines, but at this point, it is what it is.

If both cylinders are close and it starts easy, I wouldn't worry too much about compression. It's tough to get an accurate reading on small engines, most gauges have hoses that are too long.