Thumb compression test?

[redart]

Hello again.....still trying to get my 6hp '81 Sea-Horse to fire up. Fuel and spark seem to be ok, which leaves timing and compression, right?. So far I've only managed to get one pop out of it, which happened on the first pull after I blew compressed air through the carb and into the plug holes. Have removed and cleaned both the carb and the fuel pump, and installed new plugs and a new powerpack. Apart from the one pop as mentioned, cranking on the rope just turns it over, and the plugs come out covered in a wet brownish film. If I hold a lighter to the plugs when they're wet like this there's no reaction/flame, which seems odd to me. I don't have a compression tester or a flywheel puller, so before I go buy these, can anyone tell me how much pressure I should feel by putting a thumb over one of the plug holes and turning the flywheel by hand ? And is there any way to tell if the timing is way off (CD ignition) without pulling the flywheel ?. Thanks.

 

[1946Zephyr]

Re: Thumb compression test?

The wet brownish film must mean you have rust in your block somewhere. What I would do is lay the motor on it's back and dump about a cup of fuel mix into the carb. crank it real slow, to flush it all out. Make sure your plug wires are grounded out, so you don't make a flame thrower out of your outboard. I did this once with a lawn mower. I singed half of the grass and left me only half as much left to mow.

The fresh fuel mix will flush out your block and rings and get things working good again and get the "brownish film" out.

 

[redart]

Re: Thumb compression test?

Thanks for the suggestion. Quick question...should I leave the plugs in while I do this or take them out ?

 

[raczekp1]

Re: Thumb compression test?

hi.
you will measure compresion by using compresion mesurment equipment=compterion tester, you will get one rating.
using thump you will fill the air pasing by your thumb.
when you screw compresion tester insted spark plug, comptesion will hit tester but not pas by.
my jo/ev6hp 73y I get rafly 90 psi in both cylinders in 3 puls test.

to aces ignition plate you have to take of flywheel.i did puler by welding nut to steel plate and making 3 holes that fit holes in flywheel.

 

[BigB9000]

Re: Thumb compression test?

It'll blow your thumb off.
You know you can rent a puller at autozone? its like $13
bring it back (damaged or not) and get your money back.
The bolts though....they'll set you back $0.80 each (you need 3)

 

[5150abf]

Re: Thumb compression test?

A compression gauge is cheap at any auto parts store and once you have it you will use it all the time.

I check my compression 3-4 times a year, it just gives you a general idea of the engines health, kinda like taking your temperature, mine has been at 135 for quite a few years.

The actual number isn't as important as being with in 10% of each other, some engines run 90 some 140 but both are right.

Brown liquid that isn't gas sounds like a problem, could be a head gasket adn compression tester will tell you that right away.

 

[redart]

Re: Thumb compression test?

Thanks for the replies guys. Unfortunately my nearest Autozone is 7000 miles away and I don't know of any parts stores in Australia that rent out pullers. Also compression testers here will run you $50 or so, and we just lost 4-0 to Germany in the World Cup !!. Sucks to be in Australia today

A blown head gasket I can maybe replace with my limited tools and abilities. Anything more serious is probably beyond me. With both plugs out I can seal either plug hole with my thumb and keep it there with ease whilst turning the flywheel by hand. Would a compression tester pinpoint the problem to the head gasket or could it be leaking somewhere else ?

 

[butchf919]

Re: Thumb compression test?

I too have limited access to help at times.
Is it a 2 stroke? bad fuel mix
I just got done with one that had bad fuel...the smell was not good.
I would suggest this method I learned from Briggs and Stratton repair manuals,
if you have spark....put a teaspoon of gas direct into the cylinder.....replace the plugs and try it..
both cylinders need to be plugged....it may only run for a moment, but that tells you that you have a fuel issue with the carb.
If it doesn't fire, then you know you have a timing issue.
Sorry for your adventure, it can be frustrating at times.

 

[redart]

Re: Thumb compression test?

Thanks again. I tried putting a squirt of fuel in each cylinder but no joy. I know I have sparks, so timing or compression must be the issue. Is there no way to check the timing without removing the flywheel ?

 

[butchf919]

Re: Thumb compression test?

tell me the total model # and make.
timing will cause you to have a problem pulling it over if it is severe....it will try to pull your arm out....
do you know if it has points or ignition coil?

 

[redart]

Re: Thumb compression test?

It's a Johnson Sea-Horse, model # J6RCIC, which I believe is a 1981 6 hp unit. Pulling it over is a breeze - it never catches.

 

[butchf919]

Re: Thumb compression test?

made just up the road from me
so it is a 2 stroke?

 

[kenmyfam]

Re: Thumb compression test?

Using your thumb to check compression is like listening for a bad spark !!!
Just my 2 cents though.

 

[butchf919]

Re: Thumb compression test?

Using your thumb to check compression is like listening for a bad spark !!!
Just my 2 cents though.

wait a minute, I could hear that seadoo............

 

[butchf919]

Re: Thumb compression test?

It's a Johnson Sea-Horse, model # J6RCIC, which I believe is a 1981 6 hp unit. Pulling it over is a breeze - it never catches.

you know you can find
the manual on this site?

 

[Tim Frank]

Re: Thumb compression test?

Any chance the plug wires got reversed?

 

[redart]

Re: Thumb compression test?

yep, 2 stroke, 2 cylinder. CD ignition system so no points or anything to worry about. the timing plate only has one coil and one sensor on it, so I'm struggling to see how the timing could go off so far that it would stop it firing at all !

 

[boobie]

Re: Thumb compression test?

OMC didn't make a 6 hp 4 stroke back in 1981.

 

[redart]

Re: Thumb compression test?

I think you mean 2 stroke, but I agree inasmuch as the model number J6RCIC never seems to feature in online parts lists (e.g. BRP, Boats.net). The closest I've been able to find is J5RCIC and J8RCIC.
From what I've read Johnson nomenclature goes J = Johnson, 6 = 6hp, R = rope start, then CI is the year (81 from INTRODUCES), with the final C being some model variation.
If anyone can shed any light on why J6RCIC never features in parts lists I'd be mighty grateful.

 

[redart]

Re: Thumb compression test?

you know you can find
the manual on this site?

All I've been able to find is parts lists and diagrams, and links to where to buy the manual