1970 evinrude 25hp think it jumped time

[tims25]

i have a 1970 evinrude 25hp model number 25002e. I have had the motor a couple of months and have had no problems with it. Last weekend i load the boat with tent coolers fishing poles and two other passengers. The heaviest load i have had in the boat. It ran fine from the boat ramp out to the channel and then about halfway though the channel it started making a loud banging sound and died could not get it to restart on the river. Got it home and it sounds like it wants to start but wont stay running is it possible that it jumped time and if that is what it is how can i check and abount how much would it cost for someone to fix with parts and labor thanks for any input and thanks for your time

 

[lindy46]

Re: 1970 evinrude 25hp think it jumped time

By banging sound, do you mean a backfire? Or a bang like you hit something? Was the motor pumping water?

 

[tims25]

Re: 1970 evinrude 25hp think it jumped time

i didnt hit anything lound bangging from top end and yes it was pumping water

 

[fixmyevinrude]

Re: 1970 evinrude 25hp think it jumped time

By jumping time do you mean like a car engine? Your motor is a 2 stroke engine and does not have a timing chain like a 4 stroke care engine. Its possible the timing is off. I think I would first check the compression. Sounds like a possible broken ring or piston rod problem. I would also check the lower unit. You could have gear problems. I would also invest in a repair manual. Best of luck.

 

[tims25]

Re: 1970 evinrude 25hp think it jumped time

pressure is good 85 on one 87 on the other

 

[jbjennings]

Re: 1970 evinrude 25hp think it jumped time

I suggest taking out your spark plugs and turning the flywheel by hand to see if something is binding under the flywheel. If not, I'd then take the lower unit off, and hook up a water hose to the water tube and run it without the lower unit on to see if there was any "banging" then. If there was, and nothing under the flywheel is binding up, then it has to be a wrist pin or rod broken and slapping around in the crankcase, in which the powerhead would be trash. If the problem is in the lower unit you'll at least have the problem isolated to there.
Good luck,
JBJ

Just curious........is there any chance you happened to forget to put oil in your tank when you filled it up the last time?

 

[CATransplant]

Re: 1970 evinrude 25hp think it jumped time

A sheared flywheel key is a definite possibility. With your symptoms, it's the first thing I'd check.

 

[tims25]

Re: 1970 evinrude 25hp think it jumped time

had someone look at it yesterday and they said its is the main bearings you can take the crankshaft and move it up and down and side to side is this possible and how much would it cost to fix it thanks for the help in advance

 

[F_R]

Re: 1970 evinrude 25hp think it jumped time

had someone look at it yesterday and they said its is the main bearings you can take the crankshaft and move it up and down and side to side is this possible and how much would it cost to fix it thanks for the help in advance

If it truly is moving side to side, consider it unrepairable. At least unless you have access to Fort Knox.

However, damage like that doesn't happen all at once. It happens over a longer period of time, usually from water getting in where it doesn't belong and causing rusting of the bearings. But, I suppose there has to come a point where it says 'nough.

 

[fixmyevinrude]

Re: 1970 evinrude 25hp think it jumped time

I believe you should get a second opinion. Was the problem demonstrated to you? Was the person who told you this qualified to make a diagnosis? Have you tried jbjennings suggestion? Seems like a pretty severe problem to happen so quickly. Do a little more digging and keep us posted. Best of Luck.