is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

[olympic]

Hi. I'm looking at a boat purchase so hoping for a quick response. Boat has a 1988 Johnson 110HP 2 stroke oil injected motor on it. Compression is 105-107 across the cylinders. Is that too low or acceptable?

Thanks in advance for the help.

 

[itsaboattime]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

Those are good numbers. Some will say they are a little low, but I have had worse.
I have the same outboard but the '87 Evinrude. My advice it to pull the heads and clean the water passages and replace the water diverters. First thing. Then I would remove the oil injection system (VRO) and run premix.

Just my two cents.

 

[Bosunsmate]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

Yep id buy one with those numbers, run some seafoam through it or another anti carbon fluid and it should be fine.
Do the impeller and gearoil too unless you get given a receipt to say its being done recently

 

[olympic]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

Thanks for the responses. Sounds like it's good and will do a little work. Lower unit oil was done in the spring and looks good but will do it again here. Will find out about the impeller. Will also look at cleaning those water passages and replacing diverters.

 

[emdsapmgr]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

The mid to late 70's V4 engines all ran at least 125 lbs compression. Your engine has the factory low compression "bathtub" heads, so your compression is "normal". Run it.

 

[olympic]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

The mid to late 70's V4 engines all ran at least 125 lbs compression. Your engine has the factory low compression "bathtub" heads, so your compression is "normal". Run it.

Thanks for the response and reassurance!

 

[phillnjack2]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

I wouldn't touch it with such low numbers.
even a low compression engine should be atleast 110.
idealy this motor should have 130psi to135psi .
with the numbers you have its worn out, or your compression guage could be out a touch !!!!! try the guage on a good known engine
if they come up low numbers then you will know the guage is faulty.

now are you testing it when warm, with a touch of fuel running through it with carbs fully open ?
if your testing it cold and dry with butterfly's shut the numbers realy don't count, it needs to be done correctly to be precise.

if you have not already bought the boat then walk away and find one with higher numbers.
its ok if you already own it and know how its been looked after and serviced, but to buy with low numbers you could be looking at a lemon that needs a complete rebuild.

and I too would dump the vro ASAP and goto premix.

just my opinion

phill

 

[boobie]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

Phill, you know what opinions are don't you ?????????????????????

 

[Fleetwin]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

I think the numbers are fine. The good part is that they are relatively even.

I wouldn't trash the oil injection, just make sure the tank is clean and the alarm works.

Replacing or checking the diverters is not bad advice but I wouldn't do it unless you see hot spots on the head covers. You can check with an infrared gun.

Replacing the gear lube and impeller is a great idea. Make sure you replace the fill/drain plug seals!!!

 

[little.boat]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

I'm buying a 89' 200 XP and my compression is low 100's between all 6 cylinders. I am told by a lot of people and marine mechanics that those numbers are good on that motor. These were low compression motors anyway. They came from factory around 115-120

 

[olympic]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

Hi everyone and thanks for the opinions and advice. It turns out the motor is an '87 rather than an '88 and I did go ahead and buy the boat. On the fence regarding the vro. I will need to research at a minimum how to check the alarm to make sure its functional while I decide what to do. I've got a few months here as the boat probably won't see water until April at the earliest given our weather.

 

[boobie]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

Little.boat, it's not proper to high jack a thread. Please read the rules at the top of the forum. Thank You.

 

[little.boat]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

Wasn't aware I hijacked a thread I was saying I would buy the motor because from what I learned while looking at the motor I just bought that those compression numbers were ok. Maybe you should re-read my post homie.

 

[boobie]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

Don't fret, I just found something out that made me very happy and your compression is just fine on that motor.

 

[olympic]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

Don't fret, I just found something out that made me very happy...

Want to share your discovery?

...and your compression is just fine on that motor.

Must admit been a bit nervous that maybe some major mechanical issues could be on the horizon given some of the comments about it being low. Hopefully it will run fine once I can get it out on the water. I'll do the mechanical maintenance on the motor and the rest of the boat that is needed.

 

[boobie]

Re: is 105-107 compression okay for '88 Johnson 110HP 2 stroke oil-injected?

Sorry, can't share at this time, maybe later.