1968 EVINRUDE FASTWIN 18HP - COLD START PROBLEMS

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samuelh1987

Well-known member
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Dec 9, 2016
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Location
Somerset, KY
LOCATION
Somerset, KY
I came across a 1968 18hp Evinrude that appeared to be a great runner. Ran great at the sellers place, he had it running before I got there (hint), and told me it could take a few pulls to fire up from cold. Sure enough the next day it was awful, Ended up spraying fuel into cylinder to get it to start. I checked the leafs and they look new. Went ahead with a tuneup and all the usual stuff on a older motor thinking it would resolve the issue. Motor does run very well when it gets going and will restart with a single pull after initial start. Just at a loss as to what to try next.

Important info:
Compression is 120 Top / 125 Bottom
I installed a New Tune Up kit including plugs, & Wires
Gear Case Reseal
New Fuel Pump
New Hoses and gas tank
Carb Kit
Set timing with marks on flywheel, using a multimeter
 
I have been working on similar motor. In addition to the things you are doing, I suggest checking the carb linkage sync & also consider changing the upper crankshaft seal (not very hard). To be honest, I haven't tried to start mine since working on it, waiting for winter to thaw. Good luck on your project.
 
Who's tune-up kit did you use?
What all was installed?

On the carb does the choke blade close FULLY? You mentioned you had to manually place fuel into the cylinders to get it to fire.
Who's carb kit was used ? Did you pull the aluminum plug on top of the carb that cover the idle calibration holes? New packings for the idle needle?
 
Pappy said:
Who's tune-up kit did you use?
What all was installed?

On the carb does the choke blade close FULLY? You mentioned you had to manually place fuel into the cylinders to get it to fire.
Who's carb kit was used ? Did you pull the aluminum plug on top of the carb that cover the idle calibration holes? New packings for the idle needle?

Hey pappy, I went Evinrude for all parts. Learned from the past. I also removed the welch plug and cleaned the passages well. I got it to the point of being able to add fuel to the carb throat and it'll fire up. A small bit of progress. Points and condensers were replaced along with plugs wires.
 
OKay check and see that the high speed nozzle gasket is in place. If not you will have no suction to pull fuel through it for the idle circuit. Packing washers should be in the idle needle and seated. Brass pick up tubes cracked?
Richen the idle needle from whatever position it is currently in. Go another turn or two just to see if it will begin to pull fuel.
Again.....the choke valve has to be fully closed or it will not pull fuel.
 
everything within the carb looked great. What I don't understand is that it runs great once it starts & will restart with no issues. An idea I had is that Its got one of the small square fuel pumps, and it may be undersized. The 18hp I had previously had a much larger pump, could that be a issue? The pump was rebuilt and works fine once it gets going.
 

Your answer above was vague at best.
The small square pumps are barely adequate and do not handle the fuel lifting duties very well. Much prefer the larger domed pumps.
Still, if you are pumping the bulb then you are effectively taking the place of the fuel pump and the carb bowl should fill and be ready to supply fuel through the high speed circuit when choked and the idle circuit when started and idling. Pumping the bulb takes the fuel pump right out of your troubleshooting theory.
 
That's what I was thinking. So basically a fuel delivery problem within the carb. I have the slow speed needle backed out 1 turn. Its will sneeze if you go any further in and stall if it comes out much more than a quarter turn from there. I have 2 packing washers on the needle. would it be wise to add more? The carb is extremely simple, that's why I'm stumped by it. Could a float that's not set right cause a no start but then work once the motor gets going.
 
I verified that the leafs are working correctly when I redid my carb last night. I taped a piece of paper in front of the manifold and pulled engine over. Sucked the paper right in. I also adjusted the float slightly and added additional packing to the low speed needle.
 
If the low speed needle is backed out (counter clockwise) It will richen the engine. The engine will not sneeze if it is being richened.
Recommended starting point for a low speed needle is 1.5 turns from a lightly closed position anyway.
Richen your mixture and tell us what the engine does. You should have enough flexibility to almost flood the engine with fuel at idle with the needle or shut it off if turned in.
The answer is a No on the float theory.
Reeds, if damaged or open will not allow an engine to idle. Your engine was running when you bought it. Was it sneezing then?
 
Finally got motor to start up from cold. I rechecked my carb setting and made sure everything was air tight again. When watching my fuel circulate it would stop moving and go backwards after about 30 sec. Took off the fuel pump and blew through it, unfortunately, you can blow clean through the outlet tube. Tried to rebuild it and was able to blow through both sides in every combination of outlet and spring. Got another fuel pump inbound for Saturday. Hopefully Ill be in business. The motor started after a few pulls and ran great until the weird fuel pump issue.
 
So the fuel lines siphoned the carb bowl dry? Doesnt the fuel line pump bulb have a check valve in it? Seems that would prevent backflow.
 
Nope....fuel lines cannot siphon a fuel bowl dry. Yes, a primer bulb has a check valve in it.
You should be able to blow through from the inlet to the outlet. That is how the primer bulb is able to fill the fuel bowl.
What you have to remember here is that the engine does not need a fuel pump at all to run if you want to gravity feed it or just pump a bulb.
All a fuel pump does is fill the fuel bowl...period. Once full it does nothing until the needle and seat drops and puts the pump back to work.
The carburetor does all the metering and running of the engine.
 
Perhaps Im just overthinking the whole thing lol. Pertaining to the fuel pump, I was able to blow outlet to inlet and inlet to outlet. When blowing inlet to outlet there was no resistance or "quack" from the diaphragm.
 
Does the fuel pump supply fuel to the carburetor throughout the RPM range? If so, leave it alone.
The diaphragm in a fuel pump is not a valve! The diaphragm is the "pump" that oscillates back and forth with the positive and negative pulses provided by the crankcase. There are small umbrella valves in these pumps that open and close as they take advantage of the pulses provided by the diaphragm.
Your initial post on here indicated that the engine ran great once it was started from a difficult cold start.
I have given you quite a bit of information to go on. Each of your replies has evaded almost all of my questions or directions to you. In this section of the forum you will best be served by working WITH the folks with knowledge rather than around us.

 
Sorry if it seemed like I was disregarding your info, in no way did I mean to come off that way. The motor is now starting with ease and running well in my Barrell. Between rebuilding the carb again and a different fuel pump my issue has been resolved. The reason it was sneezing was that the needle was not set proper after rebuild.
 

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