psi for 1989 110HP Johnson 2 stroke?

[CH1968]

Hi Team.

What is the factory psi for this model donk?

What is an acceptable psi for this model donk still running today?

Where can I find these readings?

Cameron

 

[tashasdaddy]

Re: psi for 1989 110HP Johnson 2 stroke?

above 100 psi the higher the better, but more important is that they are within 10 % of each other.

 

[CH1968]

Re: psi for 1989 110HP Johnson 2 stroke?

thanks.

i just dd the test - 90 psi on all four holes.

+/- 2 or 3 psi difference between all four.

Is the donk had it?

Cam

 

[kenmyfam]

Re: psi for 1989 110HP Johnson 2 stroke?

I would check again with a different compression tester and compare the results. The fact that you are pretty even is a good thing. How does it run now ????

 

[bgbass.1]

Re: psi for 1989 110HP Johnson 2 stroke?

warm it up good first if it dosnt come up much then decarb. and check again

 

[tashasdaddy]

Re: psi for 1989 110HP Johnson 2 stroke?

i agree use a different guage, decarb is in the engine faq forum

 

[CH1968]

Re: psi for 1989 110HP Johnson 2 stroke?

Thanks guys.

I am very dejected over these latest results and close to giving up...

What is decarb and what do I use, how and when?

WHy shoudl decarb increase compression?

Is it normal for a 20 yo donk to lose compression?

Anyone know what psi spec was (out of factory)?

Cameron

 

[Gary H NC]

Re: psi for 1989 110HP Johnson 2 stroke?

I think about 110 psi or so on a rebuilt powerhead ,I read that here on Iboats somewhere.
I tested my 1981 and all were around 90 to 95. That was on a cold engine.I warmed it up and retested and they all read 104 to 109....
Decarbing is cleaning the cylinders with Seafoam.
Just do a forum search for decarbing,you will find plenty of info..

 

[tashasdaddy]

Re: psi for 1989 110HP Johnson 2 stroke?

decarb is in the engine faq forum

 

[CH1968]

Re: psi for 1989 110HP Johnson 2 stroke?

Thanks guys

 

[CH1968]

Re: psi for 1989 110HP Johnson 2 stroke?

My manual states to throttle at WOT and then test compression. I did not do this. Why must this be done?

Cam

 

[iwombat]

Re: psi for 1989 110HP Johnson 2 stroke?

WOT isn't really that important on a 2-stroke, so don't worry about it. Also, you can pretty much count on any compression gauge to be incorrect, sometimes as much as 40psi. Unless you calibrate it, pay no attention to the actual values, only the relative values matter. Does the motor exhibit any symptoms that make you think its time for a rebuild?

 

[CH1968]

Re: psi for 1989 110HP Johnson 2 stroke?

THanksfor that post Wombat.

I have been asked to check for compression because I have sluggish starts and overheating at high RPM (close to WOT).

THoughts?

Cam

 

[iwombat]

Re: psi for 1989 110HP Johnson 2 stroke?

Overheating is about the only reason listed to give it a check, but mostly to see if you've got a blown gasket. Your numbers are even, so you don't. Overheating is more likely either waterpump, or thermostat related. A carboned up motor will run hotter at WOT, but your cooling system should keep up. Decarb is just a good idea, so you should do it anyway.

Sluggish starts are either starting procedure, carb, primer solenoid, or ignition related (in order of most to least likely).

In my experience, trouble holding an idle and degradation of hole-shot are the signs of a worn powerhead.

 

[CH1968]

Re: psi for 1989 110HP Johnson 2 stroke?

THanks.

What happens to the primer solenoid?

How do I tell if it is faulty?

SHoudl I replace it anyway?

Cameron

 

[iwombat]

Re: psi for 1989 110HP Johnson 2 stroke?

There's some o-rings in the primer solenoid that can get worn - pretty rare. I'd check procedure and carb long before considering a primer solenoid.

 

[iwombat]

Re: psi for 1989 110HP Johnson 2 stroke?

As coincidence has it, I just wrote up a draft for the cold start procedures today.

http://forums.iboats.com/showthread.php?t=225179

 

[CH1968]

Re: psi for 1989 110HP Johnson 2 stroke?

WOT isn't really that important on a 2-stroke, so don't worry about it. Also, you can pretty much count on any compression gauge to be incorrect, sometimes as much as 40psi. Unless you calibrate it, pay no attention to the actual values, only the relative values matter. Does the motor exhibit any symptoms that make you think its time for a rebuild?

Iwombat - What other symptons shoudl I notice if it is time for a re-build??

Cam

 

[CH1968]

Re: psi for 1989 110HP Johnson 2 stroke?

SOme say on another forum that I should ditch this donk becuas eo fhte low compression.

What do you guys think I shoudl do?

 

[crb478]

Re: psi for 1989 110HP Johnson 2 stroke?

SOme say on another forum that I should ditch this donk becuas eo fhte low compression.

What do you guys think I shoudl do?

Unless you have caliberated your gauge, you don't even know that you have low compression. Your compression is even, and you can likely raise it with a decarb. I suspect that your compression is fine, and I certainly would not abandon the motor.