Logo
FULL SITE MENU

Low compression

A

achappy44

New member
hello 1981 evinrude 15 hp pull

hello 1981 evinrude 15 hp pull start. got hot and stopped running got it off the boat and did compression test got 60 on both cylinders what would cause low comp. but the same on both.
 
Rings lost temper and are now

Rings lost temper and are now just steel rings along for the ride.

That is the main reason of low compression in your situation .. good luck with it!
 
Depends on your knowledge. If

Depends on your knowledge. If I were doing it - I would have the service manual laid out and follow it. That little motor should be pretty easy .. with the tech data as a guide. Study the book before hand - It might save you.. I like to understand what I will be doing before I actually do it.. Familiarization with the manual is really helpful. plus it lets you know if you want to tackle it or not.
 
"Adam..... Compression on thos

"Adam..... Compression on those ssmall engines depends on the speed of which the engine is turning over.

However, if the engine overheated to a point whereas the engine actually seized, that causes all of the powerhead bolts to loosen up somewhat, especially the head bolts.

Before thinking about going into a overhaul project, remove the cylinder head, carefully clean the sealing surfaces of the head and block, then install a new head gasket.

Torque the head bolts to 18 to 20 foot pounds (216 to 240 inch pounds) in the following sequence.

9...10
5....6
1....2
4....3
8....7

You may be lucky.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay store at:

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"
 
"It doesnt take long for a mot

"It doesnt take long for a motor to get hot without water. Probably 30 Sec will get them to a temp of survival if stopped in time. Did yours sieze up? Temps rise pretty good in the engine to cause seizing. Good tip on the head gasket check,
Joe, I will store that one for the future.

I have had motors with good pumps cavitate and not pump water. So I check often after start, and even during operation. I think an Air Pocket can form when you first set the outboard in the water, and keeps the pump from working. Just a trait of the cooling system I guess."
 
i don't think it seized it

i don't think it seized it just died. after i got it home one of the coils had no spark so i changed it and it started. but water was hot. so i changed waterpump and cleaned thermostat and water jacket. put it back together and it pissed like a race horse and stayed cool. but it seemed to not be as fast. but it idled better. did comp. test and got 60 on both.the gasket seems like a good place to start so i will do that first. whats the best way to smooth the surface before putting it back together. redneck style no expensive machines. won't get to change it until later in the week it's my b-day and will be to drunk to fix anything.
thanks for all the help
 
Redneck style is to lay sandpa

Redneck style is to lay sandpaper on a solid flat surface and use the head like a sanding block. It will give you a fast indication if it is warped or not by where the shiney surfaces that contact the sandpaper appear.. Dull areas show the warped spots. If the entire surface is contacting the sandpaper - just lightly clean it up with the sanding method because it wont take much if it is not warped.. Happy birthday - perfect reason to drink some beeeeeeeeeeeeers.
 
"changed head gasket and she f

"changed head gasket and she fires right up on one cylinder. not firing on number one. before i took it apart it wasn't firing on number 2. i changed that coil, and it works is it possible the other is bad. and why would i continue to have a coil problem. i have also changed the power pack. and i checked the sensor and charge coil. is there something else to check or is this normal"
 
i just went out to clean out t

i just went out to clean out the engine and when i started it up the cylinder was firing. what the f. then it would fire intermittently. before it stopped and engine died. what could cause it to fire sometimes
 
"ground for number 1 is the sa

"ground for number 1 is the same as 2 wire seems fine.changed ground for power pack, and bypassed conn. for orange wire for coil. can you ohm test a coil
thanks for the help"
 
Back
Top