1975 40hp wont start

[joe_morgan]

Hi all.<br /><br />This looks like a very well organised and well populated forum. Boy am I glad to find it.<br />I've had my boat for about 3 weeks. The first time I took it out the the outboard (1975 40hp evinrude)ran well for about 20 mins. I slowed and practiced some manouvering then I noticed the engine revs would not get above 2000rpms. The throttle was at full position. Stopped and restarted ok but wouldn't get above 2000-2500 at a guess. Just when I was coming home it seemed to get back to near 3000rpm but I wanted to get back in so I didn't push it. <br />Went out yesterday morning to see if it had (miraculously lol) improved but it was hard to start (which it hadn't been previously) and ran for 5 - 10 secs each time until stopping. Revs would just fall from 1500 till dead. This happened 3-4 times till it only ran for 3-5 secs while coughing and spluttering till finally it didn't start at all. <br />Have only checked plugs which were fouled, cleaned and returned them with no improvement.<br />I'm hoping its just a fuel or timing prob.<br />Any suggestions. <br />Cheers<br />Joe

 

[rickdb1boat]

Re: 1975 40hp wont start

Hi Joe and and Welcome<br /><br />My first instinct tells me that the carbs need a good cleaning and rebuild kits. This is something you can do. The fouled plugs are good indication of carb problems or weak spark. Do you have good spark on both cylinders? If so, I would start with the carb rebuild. Maybe other have different ideas. Do you have a Manual? If not, get one from your dealer or order a Factory Manual online. Invaluble!! It will show you step by step how to rebuild the carbs. Feel free to ask questions, as that's what it's all about.. <br /><br /> Factory Manual<br /><br />Also, if you don't know when the water pump was last replaced, now would be the time to do it. Not a bad job either..

 

[jim dozier]

Re: 1975 40hp wont start

First go to the bottom of this web page and order a manual if you don't already have one (best money you will ever spend on your outboard). Second go to the FAQ page and read up on your symptoms. Your symptoms suggest fuel starvation. Begin at the tank vent, then work your way from the tank pickup, down the fuel lines, to the fuel pump, then the carbs. You are looking for obstructions (clogged vent, fuel pickup, fuel filter), air leaks (connections), bad fuel pump, clogged carbs. Don't keep running the engine until you find the problem, outboards don't like to run lean (engine damage).

 

[rickdb1boat]

Re: 1975 40hp wont start

Hi jimd<br /><br />The only thing is he said the plugs were fouled and wet. Doesn't sound like a fuel starvation problem. Sounds like too much fuel.

 

[JB]

Re: 1975 40hp wont start

What Rick said. . . or failing fuel pump.. . or water in the fuel.<br /><br />It is not usual for both carbs to gunk up at the same time. It would be more common to drop a cylinder from one carb gumming.<br /><br />When both quit working at the same time I suspect fuel supply or filter or pump.<br /><br />Good luck.

 

[AlBarrs1]

Re: 1975 40hp wont start

Joe;<br /><br />I had the same problem with an early 4-cyl Johnson 50hp I once had and a new fuel pump solved my rpm loss problem. Al

 

[joe_morgan]

Re: 1975 40hp wont start

Hi Guys, thank you all for your comments. We all weren't far from the problem. I clened the carb as recommended from countless postings I have read. I was quite clean and easy to do. Started again but was running for a few secs thwen stopping. I noticed throttle linkage wasn't moving as far as it should have been so I disconnected it and manually adjusted the throttle after starting. Runs well now. The problem appears to be in the throttle control body. Seems the cable is slipping or not moving at the very least, thus no fuel is being provided. BTW rickdb1boat thanks for the heads up about the water pump but I was assured it was done less than 1 year ago. Seems to pump water nicely.<br />So any comments on how to seperate the throttle housing. There are no visible screws that hold it together apart from the 4 that secure it on to the boat.<br />Thanks again. This forum rocks.<br />Joe

 

[rickdb1boat]

Re: 1975 40hp wont start

Not sure on that older throttle, but I believe that once you remove the throttle bolts that hold it to the boat, there will be 3 screws on the backside that you will take loose and it should separate. At least that's how my newer one works. Could also be a bad cable..

 

[joe_morgan]

Re: 1975 40hp wont start

hi shoulda added its a johnson shipmaster throttle control<br />joe

 

[OBJ]

Re: 1975 40hp wont start

Well Joe lemme add my two cents worth.<br /><br />Take the control (throttle) cable lose from the engine. Give the end a tug and see if it pulls out. That would mean the cable has come lose from the anchor point in the control or the cable is broke.<br /><br />You will have to remove the control from the mounting area to get at the back of it. The screws to hold the control together are there. As posted already, you may want to get a guide manual before taking it apart.<br /><br />Keep us posted.....thanks.

 

[joe_morgan]

Re: 1975 40hp wont start

Hi all, yes I found two screws that were hidden amongst the corrosion. It was quite easy to pull apart and clean and the two end screws that clamp the throttle cable had slipped off the cable. Thank you all. <br />Once again I am very impressed by the heavy use of this forum however I have had problems accessing this forum over the weekend. Was there a problem.<br /><br />Joe