200 hp evinrude compression psi?

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02-02-2010, 11:14 AM
bigfish5

200 hp evinrude compression psi?

i just bought a 1992 stratos 201 pro xl. it has a 1992 evinrude 200 hp outboard on it. it will start and run. it did have a none working kill switch. i checked the compression all 6 cylinders were right between 85-90 psi. i checked a few places and they said that 90-100 was excellent compression for that year model motor. so i thought i would be ok. i carried it to a shop to get the kill switch fixed. they called and said the motor was gone it has no compression? i went and picked it up and brought it home. checked it again and it was the same 85-90 on every cylinder. my question? what is normal compression for that motor? i was told that most of the older mercury's would have 115-135 psi. also that the older evinrude's like that only had 95-105 brand new from the factory? is my motor bad? or is it worth putting some money it to have everything right. also i think it need a vro pump? is there a way to take the pump off and just mix the oil with the gas? will that work or do i have to do something else to make it work? any idea's on where to find the correct compression or what i need to take off to mix the oil would be great . thanks
02-02-2010, 12:51 PM
Shellback

The most important thing is that are within 10% of each other. Your's seems to be. 85 to 90 does sounds a little low. A 250HP Yamaha I just sold ran between 105 and 110. Here's what I'd do. Get a small external gas tank that will hold a couple gallons. Then put in 1 gallon of gas, and one pint of SeaFoam. Run the motor for 15 minutes at a high idle, then shut it off and let it sit for 15 minutes. Start it again and run it hard for another 15 minutes. This will decarbonize the motor a clean up the motor and fuel system. Then recheck the compression, but first make sure you motor is up to operating temp and have the throttle wide open when performing the test. To bypass your VRO oiling system, it's just a matter of disconnecting the hoses and plugging them, and also disconnecting the electrical alarms. No need to remove the pump, as it's also the fuel pump. Just make sure anyone fueling the boat knows it needs mixed gas!!! I think you will be okay.
02-02-2010, 09:08 PM
bigfish5

but if the vro pump is bad? then it might not be pumping fuel. so then do i have to buy a vro pump or just a fuel pump?
02-02-2010, 10:11 PM
Shellback

Quote:

Originally Posted by bigfish5

but if the vro pump is bad? then it might not be pumping fuel. so then do i have to buy a vro pump or just a fuel pump?

The fuel side and the oil side of the pump are two separate mechanisms. You can disconnect the oil side and it will still pump fuel.
02-04-2010, 02:32 PM
WestTennCrappie

85-90 is a little low. Considering they are all fairly even though it should still run. It may not run exactly right, and most likely the issue will be with the idle. You would like them to all be above 90 and within 5psi of each other. Why do you think the VRo is out? If it is out and someone ran it hot replacing the head gaskets might bring it up some. Also as shellbakc said decarbonizing might bring it up some. I would think since they are so even you have enough there to make it run. And as he also said the VRo acts as the fuel pump. Just cap off the oil intake from the fuel fitting and disconnect the wires. Premix and thats it. There are some things you should be able to do yourself to get thsi running at least enough to know if its going to run like you need it too. I suspect that it will.