frozon motor

TinBoats.net

Help Support TinBoats.net:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

bowmanhere

Member
Joined
Mar 4, 2015
Messages
18
Reaction score
0
Hi have a 1969 johnson 2 stroke 4 hp motor, was running good , I did not see this but it just froze up , after it cooled off I started it and it was not peeing , I put in a new impeller and was pissing better then ever but say about 6 minutes it froze again, its 50to1 oil mix if I added more oil do you think it will be ok or will I have to open it up and do some piston work ? help and thanks bowmanhere.
 
Run a quick compression check. Sounds like you overheated your motor. Based on your description, I'd guess you're going to have to split the case and redo pistons and clean up the bore.

Adding more oil may only compound the problem, because more oil means less gas, causing your motor to run lean. That will only cause the motor to heat up again.

Run the compression check and see if both cylinders are running at 70+ and within a few psi of each other, you should be ok. I would guess that you're going to be low.

Good luck.
 
kofkorn said:
R

Adding more oil may only compound the problem, because more oil means less gas, causing your motor to run lean. That will only cause the motor to heat up again.

HUH??
That statement could not be any more incorrect if you tried.
If you don't know, without a doubt, what you are talking about...... why put it in writing and possibly mislead someone who is trying to learn something?
 
Pappy said:
kofkorn said:
R

Adding more oil may only compound the problem, because more oil means less gas, causing your motor to run lean. That will only cause the motor to heat up again.

HUH??
That statement could not be any more incorrect if you tried.
If you don't know, without a doubt, what you are talking about...... why put it in writing and possibly mislead someone who is trying to learn something?

Actually he is correct. The more oil you add the less fuel you have available for a given jet size which means going lean...unless you jet up a bit.
Probably never cause a problem with a stock 2 stroke, but in the racing 2 stroke world it can, seen it 2 seasons ago.
 
well....we are talking about a 1969 engine so I'd say it was stock as most engines on here. I do believe older engines ran at 24 to 1 ratio , so I can't see as how enriching the oil to gas would lean it out but so much. At worst I think it would foul the plugs some and cause a rough idle. But running at WOT should clear that up . Anyway to the OP if it has seized twice I'd say to hone the cyls and re-ring it to get some more life out of it. But just out of curiosity Trip was that an air cooled or a water cooled 2 stroke? Bit of a difference between a water cooled outboard and an air cooled dirt bike
 
Charger25 said:
well....we are talking about a 1969 engine so I'd say it was stock as most engines on here. I do believe older engines ran at 24 to 1 ratio , so I can't see as how enriching the oil to gas would lean it out but so much. At worst I think it would foul the plugs some and cause a rough idle. But running at WOT should clear that up . Anyway to the OP if it has seized twice I'd say to hone the cyls and re-ring it to get some more life out of it.

I agree, a person would be hard pressed to cause problems to a stock water cooled engine by doing it.
And yeah, OP if you had a couple of light seizures you could have some cylinder & ring damage. A compression test will tell the tale.




Charger25 said:
But just out of curiosity Trip was that an air cooled or a water cooled 2 stroke? Bit of a difference between a water cooled outboard and an air cooled dirt bike

Charger it's a air cooled 3 cylinder...just a bit of difference :wink:
 
Thats okay....still very incorrect, even on an air cooled bike engine.
BTW - on a water cooled isn't it amazing that the factories recommended, in writing in the Owner Manual, double oil for extended WOT or racing purposes on stock engines? Hmmmm wonder why that was? Nothing ever mentioned about a jet change either.
Back to 2-strokes in general and bike engines in particular....You can produce more power and run longer/safer by adding oil. The only jetting changes necessary were made for the overall change in viscosity of the mixture and its resultant inability to flow through a given orifice size (jet), not because the extra oil made the engine lean for the reasons stated or those that you believe.
I can back my statement up with controlled testing data (facts) ..........can you?

If so, go for it....would love to see what you have to back up that statement. Am betting we will see nothing but a not needed comment.
 
Pappy relax. I know you are correct and see why misinformation is frustrating.

Still no need to call anyone out.

Let's go fishing :)
 

Bowmanhere, it certainly sounds like your motor has either seized up from overheating or lack of oil.

Big question? Can you turn your flywheel or it still seized up. Each time it seizes up it is doing some damage to cylinder, cylinder skirts and piston. Over heating causes the piston rings to expand and causes them to narrow the clearance from the piston and the cylinder bore. Eventually they scrap up the cylinder walls or break. Hopefully there is minimal damage. If you are able to free up your power head, then recheck compression. Please let us know the out come.

- Please check your tank to see if you added oil in the gas tank. (Very easy to forget putting oil in the tank.)

- Running your motor on 24:1 will not harm your motor in the slightest bit. So, if in the future you forgot if you added oil or not, then you can always add an extra dose of 50:1 in the tank. The factory recommendation for that motor back in the day was 50:1. There more people finding low compression Evinrude and Johnson 3 and 4hp due to lack of oil. Yes, the motor can run easily on 50:1 at idle, slow troll, and mid throttle. But, at wide open those little motors tend to need more oil to help protect the connection rod from the piston's wrist pins and the crank shaft(look at parts 37, 38, 39 and 42). They are still bushings. The crank at the top has needle/roller bearings.(part 35) The needle/roller bears is considered a frictionless system (relatively speaking) and the bushing system of the connect rod to the crank and piston's wrist pin is a somewhat friction base system. So, the bushing require more oil to be lubricated.


41798.gif







Possible cooling issue.

Even though you have water coming of out the exhaust relief holes( the four little holes where the mist comes out), does not mean your power head is getting cooled adequately.

- your water jackets could be partially or full clogged up with salt, fine silt grains or fish scales. Thus preventing cooling of the head and causing an over heat situation at higher speeds.


Lightwin-cylinder-wall-water-passage-clogged.jpg



- Your water tube may have a wear hole preventing adequate water delivery to the power head. This can happen if when the gear case is being inserted back onto the lower unit housing and trying to line up the copper water tube with the impeller housing. The copper tube can be pushed up slightly and bend and thus making contact with the drive shaft. It eventually wears a hole in the water tube.









 

If you have to remove the cylinder head to inspect things then you will have get a new cylinder head gasket. I have included some information that I wrote up for another guy.


Here is some information that will help you remove the cylinder head cover and clean out the pathways and replace the cylinder head cover and gasket.





***I promise you, you will do just fine. The procedure is very simple.***


Here is a link to an online digital parts diagram of the power head.

https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1969&hp=4&model=4R69B&manufacturer=Johnson&section=Powerhead+Group


Replace the head gasket, then you will need to order one.

original OEM part number for the head gasket is 203130



Procedure:

1. Remove cowl. You will not have to remove the starter.

2. There will be 6 bolts to remove from the cylinder head. Be careful not to break off the head bolts if they seem to be stuck. If some or one seems stuck then howler back and someone will advise you how to remove the head bolts.***Not worried about this area***

Please clean any dried old sealer or clement on this bolts.

3. Once the 6 head bolts are removed then gently separate the cylinder head from the power head.

Try tapping on the side of the head with a plastic mallet or block of wood. And do it while the bolts are still in place but loose, so the head doesn't fly across the room. Works every time. Using a screwdriver can damage the paint and or damage the gasket surfaces.

4. At this point you should be able to visualize the pistons, cylinders and water jackets (pathways around the cylinders).

Pull the starter rope until both pistons are even in the cylinders. If there is crud in the water jacket pathways then clean them up. Before cleaning the water jackets or power head's cylinder head surfaces, please oil soak two small low lint rags and place them cylinders to block and prevent from getting garbage and stuff in them.




QDpowerheadwithcylinderheadoff_zpscd3a2bea.jpg


(I borrowed these pictures from a public website for better explanation.)
Also check the passages on the cylinder head it self for build up like sand, lime or silt or whatever. The pictures below is of a 3hp Evinrude/Johnson. It is an example how the trash can build up and prevent cooling of the power head.

Lightwin-cylinder-head-removing-crud.jpg



5.) If there are remains of the previous gasket on the cylinder head cover or the cylinder head it self. Then take some carburetor cleaner and apply it on the gaskets to soften or partly dissolve the gasket material. Let it soak at bit. This will make it easier to remove the remains of the head gasket without man handling and possible gouging the mating surfaces. Use a dull flat putt knife to carefully remove the remains of the head gasket.

6.) Once all of the gasket material has been removed then you want to make sure the cylinder head cover is flat and true.

You are going to use a flat surface and a figure 8 pattern of motion to true up the surface. A flat surface like a like sheet of glass or straight sheet of metal. See the diagram below.

Resurfacingacylinderhead.jpg



7. Once both mating surfaces are clean and the cylinder head is trued, then remove the oiled rags from the cylinder and make sure there is no trash, lint, grit or whatever in the cylinders.

8.) Now you can apply the cylinder head gasket.

9.) Apply a thin coat of perfect seal #4 on the threads of the cylinder head bolts. Tighten each one hand tight then you will start the torquing sequence as label above in the diagram.


Perfect seal #4 OMC part number is 0508235

It is sold online on ebay and marineengine.com and your local dealership. I believe Evinrude and Mercury dealers may have some in stock. Just supply the above order/part number.




Use a torque wrench and following the torque sequence of the head bolts.

The torque values for your motor is 60 to 80inch pounds

Here is link to torque values for the bypass covers and others.

https://www.aomci.org/cgi-bin/yabb2/YaBB.pl?num=1330642017







Your going to make 3 torquing passing with the torque wrench.

1st pass is half torque value

2nd pass is 100% torque value

3rd pass will take place after you have started and warmed up the engine to a good running temp...about 5 to 10mintues. Shut the motor off and let it cool off. Then re-torque the cylinder head bolt in the correct sequence pattern to 100% of it torque value.


All done!!! :) Now recheck your compression!!!




 
GREAT info Cajuncook1! I once fixed a 6hp Jonson that way, that someone overheated briefly ... and gave me. Did same thing to square the head too - figure 8s on glass on crocus cloth! Wish I had had all of your great info and pics at the time :) !

I also filled the OB upside-down w/ LU off and filled water passages w/ white vinegar for 2-3 days to break down any salt deposits, then flushed her well. She ran like a top afterwards!
 
Pappy said:
BTW - on a water cooled isn't it amazing that the factories recommended, in writing in the Owner Manual, double oil for extended WOT or racing purposes on stock engines? Hmmmm wonder why that was? Nothing ever mentioned about a jet change either.

It probably wouldn't have anything to do with mass produced engines being jetted on the safe side from the manufacturer would it.


Pappy said:
Back to 2-strokes in general and bike engines in particular....You can produce more power and run longer/safer by adding oil.

I'll agree you can make a little more power with extra oil....if you have out of round cylinders, scoring on the walls,etc. The oil helps with ring seal. In my situation I've taken steps to eliminate that problem, I don't want nor need extra oil.

Pappy said:
The only jetting changes necessary were made for the overall change in viscosity of the mixture and its resultant inability to flow through a given orifice size (jet), not because the extra oil made the engine lean for the reasons stated or those that you believe.
I can back my statement up with controlled testing data (facts) ..........can you?

Pappy I don't have controlled data...what some engineers or lab rats did doesn't really matter to me.
I go by real world experience.
It's all apples to oranges anyway, most small boat engines spin in the 5,000 rpm range & are tuned to run pretty much anywhere,anytime.
My stuff spins just over 10,000 rpm & is jetted on the edge. If the weather changes I need to change also or risk major damage....but that's where the power is.

OP sorry to sidetrack your post as all this has nothing to do with your problem. Hope you get it fixed and back on the water soon!

Cheer's
Gary
 

Latest posts

Top