1978 evinrude 85hp not getting full power

[GerClaire612]

I was going down the lake at full speed and the engine was running perfect. At the snap of a finger it was like it cut down to half power, and it was at full throttle. It has new fuel lines, new bulb, and new filter, but the engine still runs perfect in idle. At take off it has a little vibration, but once it is back up on plain, there is no vibration and it runs great, but still will not go to full speed. i brought the boat home, checked the compression, and all the cilinders are between 115 and 120. And ideas??

 

[Bifflefan]

Re: 1978 evinrude not getting full power

Re: 1978 evinrude not getting full power

Check the spark. probably lost a power pack.

 

[tashasdaddy]

Re: 1978 evinrude not getting full power

Re: 1978 evinrude not getting full power

welcome to iboats. 1978 WHAT????? please read this.

http://forums.iboats.com/showthread.php?t=250879

 

[glassmaster68]

Re: 1978 evinrude not getting full power

Re: 1978 evinrude not getting full power

if your spark is good,sounds like carb cleaning/kit time

 

[F_R]

Re: 1978 evinrude not getting full power

Re: 1978 evinrude not getting full power

What tashasdaddy said---1978 what?? For sure you aren't running on all cylinders--however many that is.

 

[GerClaire612]

Re: 1978 evinrude not getting full power

Re: 1978 evinrude not getting full power

i clearly stated in the title "1978 evinrude" and this is in the "johnson and evinrude outboard" catagory. But my bad, i forgot to add that it is an 85 HP

 

[bktheking]

Re: 1978 evinrude not getting full power

Re: 1978 evinrude not getting full power

They made 17 different horsepower motors in 1978, WHAT MODEL IS YOUR MOTOR???? Is it a secret?

 

[bktheking]

Re: 1978 evinrude not getting full power

Re: 1978 evinrude not getting full power

Oh ya and we can all read so chill on the retort.

 

[GerClaire612]

Re: 1978 evinrude not getting full power

Re: 1978 evinrude not getting full power

sorry for getting all pissy, i'm doing this for my computer illiterate husband and when he's on the phone and not telling me what he wants me to respond i get a little ticked at him.

He said the spark is good on all 4 cylinders.

 

[bktheking]

Re: 1978 evinrude not getting full power

Re: 1978 evinrude not getting full power

Ah jeez, the messenger, well sorry he's making you post without the pertinent info. Seems he still can't tell you what HP the motor is. From 4 cylinders it's an 85+ hp motor. Cutting out and going half speed is an indication you lose fire on a pair of cylinders, compression is good so it could only be fuel or spark. They will idle really well on 2 or 3 cylinders but chances are he checked for spark on muffs in the driveway instead of when it happened on the lake. Hard to diagnose when stuff heats up and it cools down and all comes back to life. Check wiring/grounds/coils for cracks etc etc etc.

 

[GerClaire612]

Re: 1978 evinrude 85hp not getting full power

He said he checked it in the water at the dock for spark and it was good. Would the stator have anything to do with what might be going on?

 

[bktheking]

Re: 1978 evinrude 85hp not getting full power

Maybe,he'd have to test it with a meter/dva adapter. When was the last time the carbs were serviced? That's the other part that could be an issue, fuel delivery.

 

[GerClaire612]

Re: 1978 evinrude 85hp not getting full power

The carbs were taken care of in January (right before crappie season), as well as fuel lines changed and everything else at that time, and he is planning to take the boat to a marine place to get it checked but wanted to see if anyone had any ideas what it might be so he doesn't go in and get screwed at the marine place.

 

[bktheking]

Re: 1978 evinrude 85hp not getting full power

Well I can provided you with a good PDF for testing, this site is more of a "do it yourself" kinda site. These motors are not easy to diagnose and take some special tools to figure it out. Guess he could try squeezing the bulb to see if it's a fuel delivery problem, disconnect the controls and jump start it to rule out something in the ignition switch causing it.

 

[restornator]

Re: 1978 evinrude 85hp not getting full power

unless you can diagnose which pair of cylinders aren't firing, there's really nothing you can do. Easiest way is to look at which spark plugs are real wet. If they're all dry, you know you at least have 2 that are firing and 2 that aren't getting fuel. One carburetor feeds the lower cyl's, the other feeds the top. I don't know the orientation of the powerpacks, i want to guess port and starboard. but it does sound like one fried up

 

[casey2001]

Re: 1978 evinrude 85hp not getting full power

Hi
like the guys above said make sure your getting good spark....i had the same prob my motor wouldnt run full throttle but idled fine, i pulled all my plugs and they had spark but still had the prob i couldnt figure it out until i just decided to pull one plug wire at a time and then put it back while it was running and i pulled one and there wasnt any difference. The plug was not firing under compression so i bought all new plugs and it solved the prob. the motor idled fine on 3cyl couldnt really tell a differance. maybe this will help you out

 

[GerClaire612]

Re: 1978 evinrude 85hp not getting full power

We appreciate all the info that everyone has given us, it has been very helpful. He has it at a marine shop right now and they are diagnosing it. We will let you all know what is up as soon as we know. Thank again

 

[GerClaire612]

Re: 1978 evinrude 85hp not getting full power

Found out what was wrong with the motor. Took it to a marine mechanic and the timing base plate was stuck. That caused all my problems. Instead of throwing parts at it i thought it to be cheaper to have someone else look at it. So, $150 later, i run great! Thanks for all the help and info. I know there was alot that could have caused the problem.