Help- My arm is about to fall off!

T.Rally

Recruit
Joined
Aug 14, 2006
Messages
5
Please forgive the length of this post but I'm trying to post every detail of what my problem is.

I've been using a 1975 pull start 40 hp Evinrude for the past 6 years. I always said I would convert her to electric start should she ever give me problems but since it always started with one or three pulls I didn't see the need to convert (but this not the issue). My issue is why it won't start.

Background;
The motor is mounted on 16 ft center console with a built in 20 gallon fuel tank. The tank has an anti-siphon valve at the top where the fuel line attaches to that runs to a primer bulb that is connected of course to the motor.

I had left some gas in the tank that I forgot to treat with sta-bil when I put the boat away last fall. I DID drain the fuel from the carb bowl last fall. So not wanting to use the old gas, I pumped it out using a 12 volt pump and replaced it with fresh fuel.

I attached the water hose, squeezed the primer bulb and pulled the choke lever. After about 10 pulls on the starter rope, I knew something was amiss. The primer bulb was hard as a rock but I wasn't hearing fuel entering the carb. I took off the carb, removed the bowl and sure enough the metering the vavle was stuck. Sprayed it with some carb cleaner and slapped it back on. Squeezed the primer and now I could hear the fuel entering the carb. Pulled the starter rope and still nothing. Puzzled and because I have access to quite a few parts, I changed the fuel pump (just on a hunch). Pulled the starter and it fired up and ran just like she always does. Good to go.

Next morning, I put the boat in the water and it fires right up. I putt-putt out the no wake zone and take off at full throttle. I get to my favorite crabbing area and as soon as I come off full throttle it dies and won't restart. I mess the fuel system for about an hour to no avail. On another hunch and because I didn't feel like rowing, I decide to remove the saftey feature (kids don't try this at home) on the pull starter that will only allow you to pull the starter in neutral. I put the boat in forward, open the throttle wide open and pull the starter. I nearly get thrown out of the boat, coffee goes flying, and the motor hood almost goes for a swim (I was lucky on that one, it got caught on my trotline rig).

Runs fine all the way back to the pier at full throttle. Soon as I come down off WOT, it dies. Now, I have had trouble with the primer bulb in the past. Sometimes when the motor hasn't been started in awhile I have to dissemble the bulb because it seems like one of the check valves gets stuck. Bearing this in mind and the fact it acts like it won't hold a prime, I install new primer bulb. Attach the water hose, pull the starter and still nothing. At my wits end, I decide to put it in forward and move it throttle to wide open (knowing full well it was probably going to come back to haunt me at some point). Lo and behold, she fires up I immediately move the throttle back to idle speed and it continues to run. I get a can of carb cleaner, set the throttle up a few notches and spray the cleaner into the carb in pulses making it sure the motor doesn't stall while I'm spraying. Good to go now, right?

Back to the water I go. Dump the boat in water, fires up on first pull. Go wide open out to my crabbing spot again. Come off full throttle and shes purring like a kitten. Put my first line down (about 15 minutes) and was getting ready to run it and the motor dies, again. Pull the hood off and I immediately knew something else was wrong. I could smell paint burning and could feel heat coming off the motor. Rats man, I ran it hot! Stupid impeller must have went. I row for a good hour and a half before attempting to start it again. Once I thought it was cool enough I fired it up and nursed it back to the pier.

The good news here was at least I got the fuel problem licked, bad news is of course I ran the thing hot, twice . I take it home, remove the lower unit and inspect the impeller baldes. Blades were fine but it was spun, just like a prop gets spun The blades separated from the keyed ring. Ring was turning, blades were not. I knew that no-load situation I put it in in the driveway was going to come back to haunt me. Change the impeller, fire it up, runs like a top. Back to the river go I (hell bent on catching some crabs).

Fires up, I run out to the crab line I left. Come off full throttle, purring like a kitten. Run out at full throttle to another spot, idles right down, running good. I continue this sequence, running at full throttle for a few minutes than idling for about 20 minutes, three times. On the third time, coming off full throttle it dies again. Pull the hood, motor is nice and cool. Start messing with the fuel system again, nothing. Put the boat in forward and move the throttle to wide open (I'm more prepared this time) and it takes off. I run back to the pier, come off full throttle and it dies again.

That was about 11 days ago. Here is what I've done to it since:

Checked for spark, got it.
Replaced anti-siphon valve (ASV)
Clean and inspected the pick up fitting that ASV attaches to.
Unhooked fuel supply line from carb;
Squeezed primer, I got fuel
Pulled starter rope, fuel spurts
Checked compression, exactly 100 psi in both
Installed new carb

If I spray carb cleaner into carb, it will fire but only runs on the carb cleaner than quits.

What am I missing, what am I forgetting? Any advice (besides converting to electric start) or ideas would be greatly appreciated. I am stumped, my hands are blistered and my arms are sore.

Thanks

T.Rally
 

boatingbob

Petty Officer 3rd Class
Joined
Aug 1, 2006
Messages
88
Re: Help- My arm is about to fall off!

Just a few ideas, Neutral shift sensor? or perhaps a bad ground? Do you have an overheat light or buzzer hooked up? if not it would be a good idea, gives you peace of mind.

Also could your carb linkage be out of whack?

just some ideas. I just did work on my 62 Johnson 40 not sure how similar these motors are but thats where I would start looking, specially if you can start it in gear.
 

imported_lorin

Petty Officer 2nd Class
Joined
Jun 23, 2006
Messages
199
Re: Help- My arm is about to fall off!

you might try a more complete cleaning or rebuild of the carb-spraying cleaner in doesn't do much.
 

T.Rally

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Joined
Aug 14, 2006
Messages
5
Re: Help- My arm is about to fall off!

boatingbob said:
Just a few ideas, Neutral shift sensor? or perhaps a bad ground? Do you have an overheat light or buzzer hooked up? if not it would be a good idea, gives you peace of mind.

Also could your carb linkage be out of whack?

just some ideas. I just did work on my 62 Johnson 40 not sure how similar these motors are but thats where I would start looking, specially if you can start it in gear.

I thought about the neutral switch and the vacuum cut out switch but these things essentially ground the points so there would be no spark. I'm getting spark in neutral as I visually checked it and the fact it will fire on carb cleaner in neutral.

I at one point thought about the linkage being out of whack but the fact it ran so well led me to believe it had to be something else. You got me thinking, when you put it at WOT, the amarature of course moves to advance the points. Is it possible, that the points could be bad enough that it won't start when the spark is retarded (as it is at idle) but good enough to run the motor at full throttle when the spark is advanced? Is that possible? Shoot, why would it start on carb cleaner? You would think if that were the case, at WOT it would sputter and miss. It doesn't do that. It seems to run normal at WOT. Got to be a fuel problem, right?

An alarm or light for overheating would've come in handy, for sure.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: Help- My arm is about to fall off!

Hm-m-m. Sounds like it has some thing to do with crab traps. That's no more unreasonable than some of the things you've done. All that stuff concerning asv, primer valves fuel pump, etc, have nothing to do with the motor starting. Quitting, maybe, starting no. Not as long as there is fuel in the carburetor. If there is fuel in the carburetor and if the carb is clean, as you say it is, then it should start. It is possible that there is some crud in the slow speed circuit of the carb, but you say you've changed out the whole carb.

I suggest you get your sights off the fuel system and onto the ignition system. Worn out breaker points. Bare or loose wires, especially those going to the stop button. The magneto plate mounting may be worn loose and sloppy so it flops around and you can't maintain proper points gap. All these things are affected whenever you move the throttle. And it sounds like moving the throttle kills it. Or crabs.

And stop trying to kill yourself....please. People that get thrown out of boats get run over by boats...their own as it goes around in a circle and runs over them.
 

T.Rally

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Messages
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Re: Help- My arm is about to fall off!

lorin said:
you might try a more complete cleaning or rebuild of the carb-spraying cleaner in doesn't do much.

Your right about that. Carb cleaning doesn't do a whole lot but I ended up installing a brand new carb, albeit 30 years old. Still it never had fuel put through it. It was right out of the box. No difference.

I wondering about my reeds now.
 

F_R

Supreme Mariner
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28,226
Re: Help- My arm is about to fall off!

Reeds??? Reasonable a cause as crab traps.
 

T.Rally

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Messages
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Re: Help- My arm is about to fall off!

F_R said:
Reeds??? Reasonable a cause as crab traps.

I see your point but is it possible, that the points could be bad enough that it won't start when the spark is retarded (as it is at idle) but good enough to run the motor at full throttle when the spark is advanced? Is that possible? Why than would it start on carb cleaner at idle speed? Why are my plugs not wet with gas? Dry as a bone. Got to be a fuel problem, right?
 

rwise

Captain
Joined
Jul 5, 2001
Messages
3,205
Re: Help- My arm is about to fall off!

a 30 year old part may need rebiult as well, if you can squirt fuel mix into the carb and it fires up, then I would say you have a fuel problem!
 

boatingbob

Petty Officer 3rd Class
Joined
Aug 1, 2006
Messages
88
Re: Help- My arm is about to fall off!

rwise said:
a 30 year old part may need rebiult as well, if you can squirt fuel mix into the carb and it fires up, then I would say you have a fuel problem!

Could it be the idle circuit of the carb? or even the low speed rich lean adjustment?
 

Xcusme

Commander
Joined
Apr 21, 2003
Messages
2,888
Re: Help- My arm is about to fall off!

T.Rally said:
F_R said:
Reeds??? Reasonable a cause as crab traps.

I see your point but is it possible, that the points could be bad enough that it won't start when the spark is retarded (as it is at idle) but good enough to run the motor at full throttle when the spark is advanced? Is that possible? Why than would it start on carb cleaner at idle speed? Why are my plugs not wet with gas? Dry as a bone. Got to be a fuel problem, right?

Look, why not try something totally nuts? Try pulling the flywheel and having a look at the ignition system. Inspect the points for pitting etc. Clean or replace the point sets and regap per specs. Inspect the coils for cracks , replace as necessary. Check for play in the mag advance plate that would prevent maintaining the point gap. The parts are cheap, and replacing the coils,points and condensers is easy. Plug wires would be inspected at the same time, both ends. Stop using carb cleaner to start your motor. Carb cleaner is very harsh and has no lubrication. Use fuel mix in a spray bottle instead.
 

T.Rally

Recruit
Joined
Aug 14, 2006
Messages
5
Re: Help- My arm is about to fall off!

Xcusme said:
T.Rally said:
F_R said:
Reeds??? Reasonable a cause as crab traps.

I see your point but is it possible, that the points could be bad enough that it won't start when the spark is retarded (as it is at idle) but good enough to run the motor at full throttle when the spark is advanced? Is that possible? Why than would it start on carb cleaner at idle speed? Why are my plugs not wet with gas? Dry as a bone. Got to be a fuel problem, right?

Look, why not try something totally nuts? Try pulling the flywheel and having a look at the ignition system. Inspect the points for pitting etc. Clean or replace the point sets and regap per specs. Inspect the coils for cracks , replace as necessary. Check for play in the mag advance plate that would prevent maintaining the point gap. The parts are cheap, and replacing the coils,points and condensers is easy. Plug wires would be inspected at the same time, both ends. Stop using carb cleaner to start your motor. Carb cleaner is very harsh and has no lubrication. Use fuel mix in a spray bottle instead.

Thanks. I did pull the flywheel, inspected the points and put it back together. I just can't convince it myself its an ignition problem (drat tunnel vision). The worst part is I have plenty of points, condensers, coils and such on hand. I should have went ahead and changed them. Hell, its already got all new fuel system parts, I might as well change all the ignition parts as well.
 

rwise

Captain
Joined
Jul 5, 2001
Messages
3,205
Re: Help- My arm is about to fall off!

really sounds to me like the low speed circuit in the carb (yes both of them) is stopped up. If it runs wide open it is running on the high speed circuit. take the old carb and clean all the openings/passages with carb cleaner, some soak them over night, blow air through them. be very annul about it.
 
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