1978 25hp Evinrude. won't reach highspeed(low RPM)

[smittyCrappie]

Just bought 25hp 1978 motor.It was in storage 10 years, ran only once in that time. <br /> Old man swears it only has 6 hrs on it. anyway. It idles well then just shuts off. Get it in gear and icrease throttle and it won't run at high rpm enough to plane or reach top speed.<br />it bogs down at full throttle but does just fine at a slow 15mph half throttle. Sometimes at full throttle it will give a spurt that seems like it wants to take off.

 

[smittyCrappie]

Re: 1978 25hp Evinrude. won't reach highspeed(low RPM)

one more thing. the choke has to be pulled out to get it to run at all. It smokes more than it should. I think.

 

[OBJ]

Re: 1978 25hp Evinrude. won't reach highspeed(low RPM)

Hey Smitty....welcome to iboats!<br /><br />Setting for 10 years with no maint is not good. First thing to do is get a carb kit, some carb cleaner, a six pack of Longneck Buds (optional) and clean and rebuild the carb. Probably gunked up from setting so long.<br /><br />I would also put a new pump impeller in it. The rubber impellers tend to lose there memory and don't pump real good once they are in a curved set.<br /><br />A good manual would be an asset to you. You can get the generic from iboats or reprinted OEM manuals from the links below. OEM are the preferred manual.<br /><br /> http://ww3.kencook.com/evinrudejohnsonmanuals/ <br /><br /> http://www.marineengine.com/manuals/evinrude/order_pre-1980.html <br /><br />Got any other questions, don't hesitate to post....Good Luck!

 

[smittyCrappie]

Re: 1978 25hp Evinrude. won't reach highspeed(low RPM)

thanks obj<br />I ordered the kit, impeller, and manual today. <br />Will it hurt the motor to run it fishing this weekend?

 

[OBJ]

Re: 1978 25hp Evinrude. won't reach highspeed(low RPM)

Don't think I would Smitty. You could be running in a very lean condition right now which could do some bad things to the cylinders. Ought to error on the safe side and get the engine running good first, make it reliable. Fishing is a lot more fun if you don't have worry about the engine.

 

[Chinewalker]

Re: 1978 25hp Evinrude. won't reach highspeed(low RPM)

Smitty - DO NOT run it this weekend! Your "choke" description is classic carb goo symptom. OBJ nailed it that you can burn up the motor trying to nurse it along like that. Borrow a buddy's motor, or bring your oars until your motor is healthy again. It's a good, solid design and well worth doing right the first time...<br />- Scott

 

[fireman57]

Re: 1978 25hp Evinrude. won't reach highspeed(low RPM)

If you have your parts you can take a few hours this evening and get everything done and be ready for the weekend. Enjoy your Bud's after you get the work done. You may have to soak that carb overnight to loosen 10 years of varnish. Make sure that you have the carb jets cleaned out perfectly. Use compressed air to blow them out after a good cleaning.

 

[Solittle]

Re: 1978 25hp Evinrude. won't reach highspeed(low RPM)

I wouldn't go out before changing the water pump as OBJ mentioned. If the old one breaks up it could result in bits and pieces clogging up water passages which can lead to overheating which can lead to failure.<br /><br />Also check/change the gear oil.

 

[smittyCrappie]

Re: 1978 25hp Evinrude. won't reach highspeed(low RPM)

I will get the carb fixed and change the impeller before I run the motor again. I hope I don't loose my carb parts. I am clumsy but I think if I can get a manual and do it I can save lots of money the parts are 27.00 labor is 150.00. My stuff comes monday so I am going to let it soak sunday night. I'll use the trolling motor only this weekend. Hey it is fishing.

 

[smittyCrappie]

Re: 1978 25hp Evinrude. won't reach highspeed(low RPM)

Well I just finished a few hrs ago. It was fun. My motor purrs like a kitten. BUT........I can't get the shift rod right. My shifter is in forward but my gear is neutral. shift to neutral and its reverse. What did I do wrong.

 

[Chinewalker]

Re: 1978 25hp Evinrude. won't reach highspeed(low RPM)

Hi Smitty,<br /> Did you have the detent in the shift rod aligned in the hole of the brass shift rod connector? I've had them where the tip of the ball is just inside the connector and when the bolt is inserted it clamps it in place but is out of whatck by about 3/8-inch - just enough to throw the shift off.<br />- Scott

 

[smittyCrappie]

Re: 1978 25hp Evinrude. won't reach highspeed(low RPM)

all fixed thanks for the help. I am glad I found this site. Post ya later