1970 Evinrude 40 hp float issues???

[smevil]

Ok here it goes, 1970 Evinrude 40hp carb fresh rebuild, new float, needle seat all new gaskets, etc. this problem has been on going for months, after you put the carb back together and prime the fuel bowl you hear the fuel fill the bowl, then primer bulb gets tight, as normal. Then turn key engine runs perfect. Second and third day go to prime the bulb you get 1/4 sqeeze on gets tight engine still runs perfect. Here is the problem second or third time at the lake you prime bulb and fuel comes out the top of the carb thru atmopheric hole at this point you take the bowl of bench test all is good, next time out might run great all day or not get off the dock because it comes out the top atmosheric hole on top fwd of the carb.
This has done this time and time again same senario, been in this thing 20 plus times, the one thing that is curious to me is after the 3 day window you go to prime the bulb and it will get hard and remain that way for 1 to 6 hours up to day or so then squeeze it once after walking by and its soft then out the top in comes, I already know it going to come out the top, Have bench tested the carb every way imaginable the needle and seat shuts air off when blowing perfect every time. One other thing I can't get my head around its perfect 30% of the time 70% failure rate, any ideas???

 

[F_R]

Re: 1970 Evinrude 40 hp float issues???

Have you tried installing a new float? The old one may have soaked up some gas, reducing the bouyancy.

 

[smevil]

Re: 1970 Evinrude 40 hp float issues???

Yes sir, we put in a new one but to test that theory we weighed the old cork one. and were the same.

 

[smevil]

Re: 1970 Evinrude 40 hp float issues???

Also it will stick in the up position and will not allow fuel into the bowl.

 

[F_R]

Re: 1970 Evinrude 40 hp float issues???

OK, still making wild guesses here. Have you got the clip installed correctly? No it doesn't go through the hole, if that is what you are doing. Don't laugh, people have done that.

 

[smevil]

Re: 1970 Evinrude 40 hp float issues???

Not to sound silly, but what clip?

 

[lindy46]

Re: 1970 Evinrude 40 hp float issues???

Most kits now come with a "rubber"-tipped needle and a clip which attaches to the needle and the arm of the float to keep the needle from sticking in the seat orifice.

 

[nwcove]

Re: 1970 Evinrude 40 hp float issues???

that clip comes with most new kits, but its a very small part and can easily "hide" in a corner of the bag that the kit comes in.

 

[71Windsor]

Re: 1970 Evinrude 40 hp float issues???

When you pulled your carbs did you take a close look at the pin that goes through and retains your float? Run a very small pipe cleaner through that and check again before assembly? I had a 150 in the yard same problem guy bet I wouldn't get it figured out. Turns out he over looked that pin and guide area and it had buildup but not enough to stop the pin just enough to hang it up.

 

[smevil]

Re: 1970 Evinrude 40 hp float issues???

Well thanks to all the advice I recieved, I would like to report I have the issue fixed, and motor runs like a top. going by what everybody here was saying I looked over the needle seat and put in an old float that i had removed originally from this carb, it to worked in driveway but day later on the lake same problem resurfaced, so forseeing this I was sharp enough to bring all tools required to break it all down again. So me and the girls found a nice shady beach they played in water and i pulled of the carb. This is where i did something a little different, my wife always carries a sharp knife she keeps in her bra, so I borrowed it, and seing as we were broke down again anyway I went and did something a little more drastic basically I peeled the top layer of the old cork float like it was an apple just the outside 1/16 of an inch outer edge and the top and lower concave parts, I guess i was thinking if its not the needle it must be the float so by peeling the part of the float that could contact the edge of the bowl in the most up position and the part that could touch in transition to float down and letting more fuel into the bowl. with that put it back together and fired first crank, idle and transitions to top end were crisp and no boog down and no missing. tested following day and same results were the same, good running engine with no issues. My opinion a cork float swells in fuel maybe it is the new ethenol fuel that does this because I had put in brand new float and it worked well but it to failed shortly after installing. again thanks for all the ideas and tips. Sean

 

[nwcove]

Re: 1970 Evinrude 40 hp float issues???

make sure to reseal the float!!! ....and ROFL!!!! QUOTE "This is where i did something a little different, my wife always carries a sharp knife she keeps in her bra, so I borrowed it," !!!!! :lol:

 

[smevil]

Re: 1970 Evinrude 40 hp float issues???

Thats a good point is that regular shelac. im not 100 percent sure, but that was old float am going to do the same to new float then reseal, what would you use? Thanks about the quote shes a trooper.

 

[Cal-MI]

Re: 1970 Evinrude 40 hp float issues???

Thats a good point is that regular shelac. im not 100 percent sure, but that was old float am going to do the same to new float then reseal, what would you use? Thanks about the quote shes a trooper.

Old cork floats were sealed with shellac. Shellac dissolves in alcohol. Gas stations do not warn us if they have ethanol in the fuel. We are screwed.

Maybe we should seal cork floats nowadays with epoxy?