82 evinrude 7.5 compression??

[TOPPER14FISHERMAN]

I have model e8rcnr. A 1982 7.5 hp evinrude. Does anyone know what the compression is supposed to be? I checked both cylinders last night and they were both around 68 to 70 psi . I think that sounds low but afterall, this is a 28 year old motor. Any idea of what it was when new??
I just got the motor and want to make sure it is close before i sink any money into carb repairing and what not. I'm new to this so thanks in advance for the help.

 

[AlTn]

Re: 82 evinrude 7.5 compression??

look in the top secret files for decarbing and steps to take for a motor that's new to you...

 

[raczekp1]

Re: 82 evinrude 7.5 compression??

hi.my JoEv 6hp 73y has 90psi per each cylinder.
my Jo 9.9 83y has 110 psi per each cyl.
i think 7.5 model should have around 100

 

[TOPPER14FISHERMAN]

Re: 82 evinrude 7.5 compression??

THANKS AITn. WHERE DO I FIND THE TOP SECRET FILES? I TRULY AM A ROOKIE

 

[AlTn]

Re: 82 evinrude 7.5 compression??

onthe first forum page...top...Sticky. Top Secret Files..I'da listed the link if I knew how to....anyway....lot of reading material and knowledge there

 

[eavega]

Re: 82 evinrude 7.5 compression??

Do not fret. Gauges are known to be inaccurate, I'll bet if you get another compression tester, it will read differently. Main thing is that the readings are within 10% of each other. I had a 10 HP that read 60 PSI, but dead even between the two cylinders. It ran like a top.

-E

 

[JB]

Re: 82 evinrude 7.5 compression??

60-70psi is not unusual in a healthy rope start outboard. It ain't broke, so don't fix it.

 

[TOPPER14FISHERMAN]

Re: 82 evinrude 7.5 compression??

Thanks jb . I ordered a carb repair kit yesterday. When i first cranked the engine , it ran about 20 seconds and as i pushed the choke back in, id died. It had some old mixed gas in the bowl and i think it just ran out. I mixed fresh ethanol free 87 oct at 50 to 1 and nothing happened. So far i've cleaned/blown out the fuel lines and the screen on the water pump is clean. With the gas line unconnected at the carb, i can squeeze the bulb and gas gets through. It does get fire but the new plugs are dry. I can only assume that the carb is stopped up. The repair kit should be here by tuesday. Again, compression, clean lines and fire. Carb?? What do you think? Thanks, keith

 

[AlTn]

Re: 82 evinrude 7.5 compression??

you're there...make sure you remove the core plug on top of the carb and clean the well and 3 tiny holes you'll find under it...your kit will contain a new plug...I use a drive extension..3/8" I think...to seal the core plug back in...convex side up...plenty of carb cleaning tips in numerous posts on here..on reinstall..make sure the roller on your carb linkage is centered on the timing cam mark and the throttle plate is just beginning to open...this should happen when you have the twist handle at or near the start position...also, the throttle plate should be horizontal at wot with the roller on the highest part of the timing cam plate

 

[TOPPER14FISHERMAN]

Re: 82 evinrude 7.5 compression??

AITn, thanks. My carb repair kit isn't in yet but last night, I took the intake off to "study" the situation more. I unhooked the fuel line where it connects to the carb and squeezed the bulb. A stedy flow of gas came out. Just for the heck of it, I tapped on the carb a few times with a wrench. I installed new plugs . I re installed the fuel line, choked it, turned the throttle on full and... it fired up again and I was able to rev the motor a few times. As I pushed the choke back in slowly, it died again and wouldn't restart. From what I've read, the procedure is to place the throttle in the start position. My tiller handle has no markings on it . Can you tell me about what/where the start position is? Also, the lever for rich/lean may be adjusted wrong. Do you know approximately where that should be set for sunny East Alabama? With the airbox off, the screw can turn in about 5 revolutions before it is in all the way so I have it set right now at 2and1/2 turns back. Any wisdom?? Thanks, Keith