1968 18 HP Evinrude Won't Start

[CTyndall]

Ok, my husband and I are new to boating and just bought a 16 ft Jon Boat with a 1968 18 Hp Evinrude motor. It started fine when we first put it in the water and then when we slowed down it seemed like it stalled and then just wouldn't start. Now we can't seem to get it started. From reading the forums we have checked to see if we have sparks and we do. The gasoline/oil mixture came with the boat which had not been used in several months. Can anyone give us any suggestions on what to look at to try to get this problem fixed?

 

[tmcalavy]

Re: 1968 18 HP Evinrude Won't Start

In order to run, it has to have compression, spark, fuel and air. You have spark and air cause it started and ran before. Check compression and ditch the old fuel, clean the tank and line and maybe the carb, put some fresh gas in (50:1) and see it if will go again. Old gas gets gummy and gums up your carb...best way to fix it is to pull and clean the carb. Do you get a strong, blue spark that will jump a 1/4-inch gap?

 

[CTyndall]

Re: 1968 18 HP Evinrude Won't Start

Thanks so much for the info. The fuel has been removed and we are going to start fresh with the new mixture tomorrow. Can you tell me how to check the compression and if the problem is compession how do we go about fixing that?

 

[tx1961whaler]

Re: 1968 18 HP Evinrude Won't Start

Compression is measured with a pressure gauge that screws into the spark plug holes. You can sometimes borrow a compression gauge at the auto parts store.
What you would do is take out both spark plugs, screw the gauge into one of the spark plug holes, and pull the motor 5 or 6 times and note the pressure reached. Reset the gauge, and repeat for the other cylinder. The pressure readings should be within about 5 pounds of one another.

It really sounds like a fuel problem, though.

 

[samo_ott]

Re: 1968 18 HP Evinrude Won't Start

I concur. Ditch the old fuel and clean it up. It sounds fuel related.

To answer your question, if your compression is low you're could be in trouble but we'll cross that when we come to it.

 

[buddybarnhill]

Re: 1968 18 HP Evinrude Won't Start

i stay with the teory of the old fuel but also not it is a 1968 so even if you get it running with new fuel and all i would still have it a overall done cause someone may tell you yeah i took care of the engine but you never no better be safe than sorry

 

[CTyndall]

Re: 1968 18 HP Evinrude Won't Start

Ok, switched the fuel and put new plugs in and its start fine. The problem now is that when when we try to slow halfway to idle it stalls. Once we are on the faster then halfway we are fine and could run forever. Any ideas?
Casey

 

[tbfosback]

Re: 1968 18 HP Evinrude Won't Start

Sounds like the low speed jet needs setting. Or a poss. carb rebuild. I would try setting the jet first. Just go under the top secret file "how do I adjust my carb"
here you go
http://forums.iboats.com/showthread.php?t=167352