1967 6hp SeaHorse only runs with fuel sprayed in carb

[JohnMcL2000]

This is my second post. Got some good suggestions the first time, but still at a loss as to why this engine will only run when fuel is sprayed into the carb.

New float, checked with Johnson gauge: level and drop OK,
cleaned all parts of the carb,
needle valve looks OK, no dents or dings,
jets [high and low speed] all clear of gunk,
valve turned in to seat and backed out 2 turns,
new 'boss' gasket and other gaskets installed,
with hose to carb off, fuel flows when cranked,
fuel drains from bowl when bulb is squeezed [drain screw removed],
roller hits cam at mark, opens throttle a tad,
good spark at plugs,
points set to .020, plugs to .030
new thermostat and good water flow,

If I spray fuel, it runs fine. Guess I'll just get a 6 gallon spray bottle and exercise my 'shooting' finger...:~}

Next step appears to be repair shop...or boat anchor...j/k

 

[Vic.S]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

Carb still not completely clean or you have assembled it wrongly.

cant be anything wrong with anything else if it pumps fuel into the float chamber Ok and runs Ok when fuel is sprayed in.

 

["G"]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

John,
Your next step is to check the reed plate behind the carbs. They may be chipped, broken or they just plain don't seat against the reed block any more. I didn't read anything that said what your compression readings were. The first rule in outboard motor repair is ALWAYS check the compression. When you have checked the compression you assure you are working on a viable motor. BTW; look at the lower unit oil while you're at it. That is the next big ticket item to go wrong. One thing in your favor, the engine runs. You may be lucky and just have chipped or broken reeds. That's not so bad. Good luck!

 

[Mas]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

I'm betting you still have some crap in the carb somewhere in the idle circuit. Did you completely disassemble carb and blow out every orifice with compressed air and chase with a very fine wire?

How many turns out from gently seated is your low speed needle?


MAS

 

[crxess]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

When cleaning my 6 hp carb last week, I used a can of carb cleaner. You can confirm clear passages by watching the liquid flow.
The back side of compression is fuel draw. Weak compression will also relate to no fuel draw.

Is the carb throat getting wet at all around the choke plate?

 

[1946Zephyr]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

There was a time I rebuilt the carb on an old 10 horse. The previous owner had turned the low speed needle down to tight and broke the tip off. The tip was stuck in the hole that it seats in and no fuel could go in to the venturi. One thing you could do is remove the needle and spray carb cleaner into where it goes and see if is goes into the venturi.

 

[jay_merrill]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

There is an expansion plug in the top of the carb, which provides access to the slow speed "circuit." If you did not remove that plug to inspect and clean the applicable area, you may have bits of junk in it. Since the slow speed orifices are in that area, and are very small, that's all it would take to give you problems.

While I understand the point being made about leaf valve problems, issues such as yours are usually related to carburetor problems. Don't write off the idea of problems in the intake manifold, but start with the more likely and easiest issues first.

 

[freddyray21]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

This is my second post. Got some good suggestions the first time, but still at a loss as to why this engine will only run when fuel is sprayed into the carb.

valve turned in to seat and backed out 2 turns,

assuming the carb is clean which remains to be seen, the low speed knob should only be opened about 1 turn to start. the high speed knob if it has one to about 1/2 turn. 2 turns is way too much

 

[JohnMcL2000]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

G, thanks for responding. I bought a compression gauge and tested the engine. Both cylinders register between 85-87 on the gauge.
I drained the lower unit oil and refilled with fresh oil.
I'll try a few more things before I do as you suggest and take it apart to check the reed plate. thanks again.

 

[JohnMcL2000]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

I'm betting you still have some crap in the carb somewhere in the idle circuit. Did you completely disassemble carb and blow out every orifice with compressed air and chase with a very fine wire?

How many turns out from gently seated is your low speed needle?


MAS

Thanks for your suggestion. I took the carb apart again and blew it out with compressed air. Then ran a thin wire thru every opening. Popped the core plug off and ran the wire through there too. [$4 to replace that tiny plug!] Then I sprayed WD-40 thru and oil came out every time thru every port.
Low speed needle is backed out 2 turns from gently seated. I also tried 1 1/2 turns, 1 turn, 1/2 turn, 2 1/2 turns...
Still no luck, runs with fuel sprayed in carb only.

Compression is between 85-87 on both cylinders.
Again, thanks for helping.

 

[JohnMcL2000]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

There is an expansion plug in the top of the carb, which provides access to the slow speed "circuit." If you did not remove that plug to inspect and clean the applicable area, you may have bits of junk in it. Since the slow speed orifices are in that area, and are very small, that's all it would take to give you problems.

While I understand the point being made about leaf valve problems, issues such as yours are usually related to carburetor problems. Don't write off the idea of problems in the intake manifold, but start with the more likely and easiest issues first.

Jay, thanks for responding.
I popped the core plug out...all clean in there. Replace it with a new plug [$4..!].
Compression is between 85-87 on both cylinders.
Still won't run w/o fuel being sprayed in the carb...
Again, thanks for helping.

 

[crxess]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

Drain the carb. Pull the fuel hose off the carb. Push one end of a clean hose on the carb. Blow through the hose. Can you hear air moving through the carb or do you feel back pressure while blowing?

While the hose is off squeeze the bulb. does fuel flow out the end of the hose? If no, pull the line on the opposite side of the pump and test. fuel flow here?

Have you replaced the fuel lines? Hoses can separate over time. A separated hose can collapse internally under pressure and stop flow.

 

[Evinrude Boater]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

You seem to have cleaned the carb thoroughly and still you have too much air for the fuel supplied. Have you checked for air leaks on the carb and manifold gasket etc? Maybe one of the lead shots is missing. Is the manifold gasket torn or missing?

 

[tx1961whaler]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

I'll go back to the very first post:
How was the spark verified? Was a spark tester used, or a spark plug?

 

[jay_merrill]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

Have you tried choking the engine when trying to start it? If not and you do try with positive results, I would say that the carb is sucking air somewhere. This will alter the fuel/air ratio and cause problems.

One of the common places for this to happen, is at the throttle butterfly shaft. Sometimes the carburetor casing becomes worn and allows air to be sucked into the throat of the carb, around the shaft. If you think this is a possibility, try coating the external ends of the shaft with a heavy grease. This is not a premanent fix, but it may confirm the problem.

One thing that is kind of curious, though, is that if you are getting enough fuel via the fuel pump, proper adjustment of the float, proper LS needle valve adjustment, and a clean low speed "circuit," adding a bunch more fuel shouldn't solve the problem, while altering the air flow might.

Do you have another fuel pump and tank to try? I'm wondering if you are getting too little fuel due to one or both of your original components.

 

[Tim Frank]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

The fact that the motor runs when fuel is sprayed in the carb throat suggests that it is more likely a carb issue than reed valves.
I have never owned a motor that had reed valve probs...nor do I know anyone who has....and all I mean by that comment is that on frequency alone, carb problems rule. I don't argue that reed faults occur, but in troubleshooting I always eliminate in order of probability. At the end of this you may be one of the few that have reed trouble....but the odds are....

A few questions I would try to answer:
1) When it starts after spraying fuel, how long does it run? Does it burn off only the fuel that was sprayed, or does also it burn some fuel from the carb bowl? You could do a before and after residual fuel measure to gauge the result.
2) Is your fuel pump really OK? You may need to get a metric on the fuel pump output. Qualitative observation is often OK..."strong" spark, "healthy" fuel stream etc., but like an actual spark gap jump measurement sometimes you need to know how "healty" that fuel pump really is under load. Do you have a pressure/vacuum gauge?
3) Same thing with suction pressureIs intake vacuum OK? You may want to measure the actual vacuum that the motor develops. That will pinpoint a possible leak or point you elsewhere...maybe the reeds.

 

[Rick.]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

Did you do the compression check with both plugs removed at the same time?
I am of the opinion your carb. is not clean enough somewhere. Given the amount of time your spending on this why don't you tear the carb. down and soak it for a few days in carb. cleaner then spray the orifices from both directions with compressed air and then put it back together. If you haven't already put a new kit in it do it as well. Pay close attention to make sure your getting alll the parts in the right place. Be certain to use the seat gasket between the body and the float valve seat. If your fuel pump is weak the motor should stilll start via the bulb pumping (and your comments indicate the pump works anyway) so I keep thinking there is no gas leaving your carb. Follow this link to the 68 carb. diagram for parts placement. I am assuming the 67 and 68 carbs are the same but I don't know that for fact. Best of luck. Rick.
http://shop2.evinrude.com/ext/index.aspx?s1=32c5f8bd83d0ba469af05840647c60b9

 

[GeneMachine]

Re: 1967 6hp SeaHorse only runs with fuel sprayed in carb

Yea even with a reed broken or chipped or even completely missing it would still run