Evinrude 9.5

[1-old-outboard]

Working on a Evinrude 9.5. Just pulling it over without touching it I had 75 and 80 on the compression tester. Carb looked like 10 years of not running. Cleaned it up, new coils and wires. It does seem to run fair mid-range on up. I am seeing some exhaust in the outlet spray. It doesnt seem to be overheating. Kind of wondering if I need to pull the head and check the head gasket…..or do these exhaust separator plates have a tendency to fail? I had some hope with that mediocre compression. Any thoughts?
Thanks,
Randy

[frankr]

Exhaust spray out the blowhole in the backside? Hey man, that’s normal. That is the exhaust relief for better starting and slow speed operation.

[johnyrude200]

that’s not mediocre compression. That’s actually very good compression even with a drill gun on the flywheel turning it over. Hand crank, anything north of 60 is a good motor. I’ve never seen one (and I’ve worked on about 100 of them) above 85-90…even soaking wet with fogging oil.

Dry numbers, cold, on my guage that are 65-70 yields (all things being equal) a very smooth and low idling motor with plenty of top end. They idle down so low you can just about see the flywheel turning.

Very much like the old 6hp motors when idling low (which generally are less tolerant to the abuses of high hours compared to the 9.5’s IMHO).

[fleetwin]

Everything sounds normal for these engines to me….
Are you saying the engine won’t idle?

[1-old-outboard]

Yes I cant get it to turn down to a decent idle. That is why I thought maybe I was tossing some exhaust gas out the wrong slot. Well sounds like I have to pull down that carb again. Thanks,
Randy

[johnyrude200]

Can you elaborate on how it’s running at low RPM? Stalling out via a sneeze? Dying off slowly or say, rapidly (as in below a certain RPM it just dies off)?

A bad low idle could be due to an exhaust leak from the skirt (if the cover is on), or something as simple as a spec of dirt in the low-speed orifice/jets/venturi bleed holes. Or the timing is wrong…or an ignition issue…or someone goofed up carb air passages…or many other things.

As you probably already know, you have to go through the diagnostic process to figure out the route of the problem. Plenty of folks here with a lot more knowledge than me, but figured I’d offer up my $0.02.

[1-old-outboard]

FYI, the cut off is rapid, usually slightly after coming off the ramp for the carb. I don’t see a mark on the ramp to time to. This one has had a mouse living in it and wasting in it so the corrosion was pretty hefty. I do see the throttle handle indicator doesn’t match up with the running positions on the advance. I don’t typically look at that figuring it was just installed off kilter. This is a sliding rod affair so maybe I am that far out of time. There is also a blue (lawnmower) type fuel hose on there. I do see a lot of air bubbles in there while running. When it gets down to the stall point I try to squeeze the bulb to see if it is starving, it’s death comes a little too quickly. There still seems to be a fair amount of fuel in the bowl when I pull the drain screw. I did clean out the idle jets to what I thought was very functional. I could get a nice mist in the venturi when spraying carb cleaner tight into the idle screw jet base. Normally I don’t have a clear fuel hose and couldn’t see the flow, so I didn’t know if air in that line would be normal. I can pump the line up to firm pressure without any leaks. Thanks,
Randy

[johnyrude200]

There is a timing link n sync mark on the throttle cam. Start there to get things timed properly. It has to be pretty close.

I dont understand what youre describing – is it stalling out after coming down off high RPM? Is the cover on or off?

Testing on boat or test tank (not a garbage can filled with water)?

Does it start easily?

[1-old-outboard]

Yes it is stalling as coming down from high rpm. Cover is off with clean air blowing through (no recircing exhaust). Testing in a tank like we use at Tomahawk (55 gal drum). I will take a look at that cam again. Thanks

[johnyrude200]

If its a quick stall, as in a sneeze then dead, either the timing is off or its running lean. If it just dies off more gradually then its a fuel delivery issue.

Running in a drum is hard to calibrate these motors due to exhaust ingestion. Use a shop fan to blow fresh air on it to rule it out.

You can try turning the mixture setting up; or put the cover back on. They run lean with the covers off and will do just what you describe when trying to calibrate in that scenario.

Usually once calibrated in my 300-gallon test tank, when I put the cover on the mixture setting has to be turned leaner by a 1/4 – 1/2 turn otherwise it dies off at low idle/blubbers out.

Dont rule out a speck of dirt in your low speed orifice/jet. Those 2-3 little holes in the venturi can get clogged easily. Ive used a piece of fine wire to poke those holes and then the motor runs perfect. Theyre very sensitive.

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