25hp Evinrude problems (I'm stumped)

Hey guys, I've got a 1975 Evinrude on my jon boat. I used it all winter during duck season with no problems but then parked it until a few weeks ago. In preparation to take it on a weekend fishing trip I ran it in a local lake and though it took a while to crank it ran good for the first 15 minutes. After letting the dog swim around I headed back in and it choked out on me. I discovered that the primer bulb wasnt staying hard so I used the trolling motor to limp in. I went home and replaced the fuel line and tank. While I was at it I pulled the carb off and rebuilt it and replaced the old fuel lines in the motor. While changing the spark plugs I broke the brittle wire so I replaced the ignition coils too.

After doing all of this I tried to crank the motor and got nothing. It would back fire but didn't sound like it even wanted to crank. I tested the compression and it's a little over 120 on both cylinders. So I tested for spark and both plugs are firing. This tells me that it's still not getting fuel but I've followed it from tank to carb and gas is flowing correctly.

So why won't this thing crank?!?! It's driving me nuts!

I am no expert, and you will, no doubt, get some good advice soon.

However, I'd squirt a bit of fuel into the carb and see if she fired and then died. If so, I'd go back and look at all of the fuel connections. Maybe the bulb (with its one way valve) was put in backwards??? R

Check the fuel pump?

Steve

acwd said:

Check the fuel pump?

Steve

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Yes I did and it is working properly. I'm confident that fuel is making it from the tank to the carb and I'm using fresh gas too. Anybody else have a suggestion? Could the timing be off and need adjustment or is that even possible on these motors? I really don't want to pay a shop to fix this because cash is tight but I need to have this motor ready for the early teal season next month.

Brad

make sure pluga and wires are connected correctly, metal band on wire goes to top plug.

If your primer still doesn't stay hard you most likely have fuel pump problems,or an air leak.

Check your flywheel key

If the engine backfires quite hard while cranking then your plug wires are backward. Switch them and let us know.
BTW - the primer bulb will never stay hard while running your engine. It is on the suction side of the fuel pump! No pressure is ever in that bulb unless you are squeezing it by hand.

ultra353 said:

Check your flywheel key

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Can you elaborate on this a little more please?

Pappy said:

If the engine backfires quite hard while cranking then your plug wires are backward. Switch them and let us know.
BTW - the primer bulb will never stay hard while running your engine. It is on the suction side of the fuel pump! No pressure is ever in that bulb unless you are squeezing it by hand.

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I put the new coils and wires on exactly like the old ones came off. The top coil leads to the top plug and the bottom to the bottom plug. Is this not the correct orientation? Either way I'll take a look at this after work and see if this is my problem.

Thanks for all the help thus far.

Ok, first can you squeeze the primer bulb and it gets hard? Might take a couple of squeezes to get hard. Next, Have you pulled the plugs out and checked them to see if they are wet or dry? did you changed the plugs? The flywheel key is in between the flywheel and the end of the crankshaft. If it has a recoil starter you have to remove it and then there is a nut that holds the flywheel, remove the nut and you might be able to see the key in the keyway. If not you will have to pull the flywheel and you will need a puller for that. When you rebuilt the carb, Did you have someone soak it in carb cleaner overnight? Or just took it apart and sprayed it with carb cleaner and put it back together? Might have a passage or a jet thats still plugged.( Dont ask how I know that!)

Steve

acwd said:

Ok, first can you squeeze the primer bulb and it gets hard? Might take a couple of squeezes to get hard. Next, Have you pulled the plugs out and checked them to see if they are wet or dry? did you changed the plugs? The flywheel key is in between the flywheel and the end of the crankshaft. If it has a recoil starter you have to remove it and then there is a nut that holds the flywheel, remove the nut and you might be able to see the key in the keyway. If not you will have to pull the flywheel and you will need a puller for that. When you rebuilt the carb, Did you have someone soak it in carb cleaner overnight? Or just took it apart and sprayed it with carb cleaner and put it back together? Might have a passage or a jet thats still plugged.( Dont ask how I know that!)

Steve

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Yes the primer bulb gets hard. I put new plugs in and they were wet when I checked them. I'm not familiar with the flywheel key but what exactly does looking at it tell me? I didn't soak the carb just sprayed it off but since the plugs are wet doesn't that prove fuel if passing through?

The plugs being wet means you got it flooded. Take the plugs out and crank it over to dry the cylinders out. If it has a recoil starter give it about 10 to 12 pulls. Do you still have the old plugs? If so put them back in AFTER you cranked it over. Do not choke it and try and start it, if it fires off and runs let it run for a bit so it will finish burning the raw gas out. If it doesnt run check the plugs again and if they are wet then something is causing it to flood, float stuck open,etc. The flywheel key if it shears it will make the timing off and make it not run and backfire or do nothing at all.

Steve

Thanks, I'll give that a try when I get home this evening.

Well I've finally got the motor running right and I'm a little embarrassed to say what the problem ended up being. After rebuilding the carb, replacing every inch of fuel line, rebuilding the fuel pump, replacing the fuel tank as well as the ignition coils and spark plugs, and pulling the flywheel I noticed the problem. I had taken the motor to a shop to have a mechanic look at it and he discovered a broken wire on one of the ignition coils. He replaced them both for me and apparently he got the wires crossed. So I've gone through the whole motor and yesterday I swapped the plug wires just to see and she fired right up and purred like a kitten. I felt pretty silly but I'm just happy to have it running again.

Thanks to everyone that offered your knowledge to help me figure this out. It was certainly a lesson learned for me.

Crossed plug wires? Hmmmm I believe that was mentioned quite a while ago......

I may be wrong but, I think he was saying the wires under the flywheel going to the coils . Anyway glad to hear ya go it going!

God news....and......Just like Thomas Edison,.....you now know a whole lot more about things that can go wrong in the future. At least it didn't take 10,000 tries......regards, Rich

AND...you just tuned your engine for the next season!!!
Nice pre-planning, Sir.

Yes pappy you were correct from the beginning. It was my mistake for trusting the mechanic that was standing beside me telling me where to put them. Now I know better and like already mentioned, my motor got alot of new stuff that it probably needed anyway. I should be good to go for the upcoming duck season.

Thanks again for all the replies.

Brad