Fuel, Air, Fire

Sounds like I would check the spark plugs. Either change them outright or do a spark test. The carb bowl may have a drain **** to let water off. Screw on the bottom. If you loosen that and gas flows then it is at least getting into the bowl. Both of those are pretty quick things to check. Best to do an overall "tune-up" including cleaning the carb etc.

120 Miles a lot of motor.

 

See if you're getting spark first, pull a spark plug, put the wire back on, ground it against the block and crank the engine.
Look on youtube for a video showing a good spark, easier to understand if you see it.
If you have a GOOD spark it's the fuel system, no spark or weak spark = electrical.
Always start here, easiest thing to check off the list with no disassembly.

 

If it was working fine (up to temperature) and then sputtered down and died, I'd think it was a fuel blockage of some kind. If the fuel supply is fine, then that leaves the carburettor. Assuming the carb has never been cleaned or generally overhauled, take the top off and look for a blocked jet. If the spark plug is a dry, light grey colour when you pull it to test, it's even more likely a fuel blockage somewhere.

One other less likely possibility is engine overheat. Do you check the tell-tale regularly? Are you getting water flow (even when the engine is cranking)?

 

As others have stated plus a couple things....

New plugs first. Even a weak spark in a two stroke might give you issues. I can't remember how many times I've put in new plugs and the damn things start.

If you have spark and new plugs, drain the bowl. If you drain the bowl, the engine starts, then dies a while later, disassemble and clean the carb, careful attention to the jets. There could very well be water or crap floating around in the bowl that does not all come out with a drain. Eventually, it will make it back to the jets.

 

Had my 8hp Mercury running great with no issues and it just died. Nothing would get it to start as I went through all the solutions for possible issues. Turns out I wasn't getting spark. Hauled it off using my halyard at the slip and did a proper test on it with a meter and turns out that both coils failed.

 

As others have said, fuel, spark, air. Crank it, pull the plug and smell it. Does it smell of gas? No? Maybe the jets are blocked with grit or water. I don't know if the engine has one of those keys with a lanyard so if you go over board the key is pulled shutting off the engine. If this was my engine, I'd change the plugs out first. 15 hp, dual cylinders,mmmmm...wait....mmmmmm........... both plugs going at the same time???? don't think so, either ignition module ($$$$$$) or bad fuel. Alex, I'll take bad fuel (water infested) for 200 dollars. Drain the carburetor bowl and watch for water.

 

Might want to do a compression test. I find most small two strokes won't run if it's under 90 psi.

 

I have plenty of compression in mine. I'm honestly about ready to let the damn boat sink or put a for sale sign on it. The past 3 years I've had rigging failures and engine issues that were supposedly "solved" by the last place that worked on it. I called them up and they said I can bring it in, but they're back logged and won't get to me till mid June. Either way, I'm not getting spark so I'm having a friend look at it. All I know is the VA doesn't pay me much and if it can't be fixed reasonably priced the boat isn't gonna move till she's hauled for the winter.

 

Obviously you should check for 'spark'; if 'spark', then consider to clean out/rebuild the carburetor.

If the engine 'died' when operating (and there is no spark), such would suggest the following:
1. loose or broken ground 'pigtail' wire from the magneto base to the engine frame. This pigtail 'grounds' the magneto to the engine, can become quite brittle and break inside the insulation; or, the connections can become loosened or corroded .... if corroded, when the corrosion drys out from engine heat the corrosion will become an insulator.
2. High tension spark plug wire cracked .... If original, immediately replace ... same as #1 above.
3, Broken or worn 'points'. The cam follower that operates the 'points' is 'bakelite' and unless constantly 'greased' can easily wear down causing the points to not correctly open.

If spark, then obviously check for compression:
1. blown head gasket. These old engine should have their cylinder heads re-torqued down on a routine basis to prevent blowing a head gasket
2. Broken 'reed'
3. Leaking seals on the crankshaft .... permits excess air (as a leak) to enter the combustion chamber which can significantly 'lean out' the air/fuel mixture. The worst scenario for a leaking crankshaft seal is a burned through piston top.

4. Carburetor:
First check for water in the tank, If no water then open and remove the main jet screw (counting the exact number and fractional number of turns it takes to remove and to correctly re-install later) and drain the fuel (and or water) from the carb bowl. If water, this is probably 'phase separation' of ethanolated gasoline. A very common ailment for 2 stroke engines that will cause immediate shutdown, even while running. Some Evinrude carburetor bowls have drain plugs.
NEVER EVER use ethanolated gasoline that is more than 45-60 days old, unless you also use the 'correct' stabilizer.

Evinrude/Johnson Parts: still available online from many 'online' sources. Bombardier Ltd. is the current owner of Evinrude/Johnson and has a very large parts distribution network. For obsolete parts, try eBay.

 

Wow thanks for all the awesome advice everyone. I'm going to spend a good chunk of time this weekend trying to dig into the issue.

I've spent a lot of time working on old truck engines, especially 85'-95' Ford models (I rebuilt an 90' Bronco last year) but haven't ever touched a 2 stroke. Any favorites idiot's guides for working on them? I have the original owner's manual for the Evinrude but it isn't all that informative. Especially helpful would be any guides on removing the spark plugs and how to work on the carb. The owner's manual doesn't have the best diagrams for all this.

I imagine I'll aim to haul it up on the halyard to be able to look at it without falling into the water.

 

Wow thanks for all the awesome advice everyone. I'm going to spend a good chunk of time this weekend trying to dig into the issue.

I've spent a lot of time working on old truck engines, especially 85'-95' Ford models (I rebuilt an 90' Bronco last year) but haven't ever touched a 2 stroke. Any favorites idiot's guides for working on them? I have the original owner's manual for the Evinrude but it isn't all that informative. Especially helpful would be any guides on removing the spark plugs and how to work on the carb. The owner's manual doesn't have the best diagrams for all this.

I imagine I'll aim to haul it up on the halyard to be able to look at it without falling into the water.

Start here for detailed, 'exploded view' in sections, of your outboard.
If you've tinkered with IC engines in the past, the exploded views in the parts identification portions will definitely help in analyzing the componentry. All you need is the year built and model number - found on its attached "Model ID plate":
OEM Parts

Caberg's above post will also be very helpful.

 

You should be able to find the service manual, as opposed to the owner's manual, on ebay. I was able to buy the service manual for a 1968 Evinrude 2 hp and it walked me through rebuilding the carb. All the parts are available online. I am NOT mechanically inclined but found working on this old 2 stroke pretty straightforward and actually kind of fun. But I was doing it over the winter without a timeline.

Here's one:

Evinrude Outboard Motor Service Manual 9 9 15 HP Models 1980 | eBay

 

You've gotten some good advice here, and finding a good manual for that engine will not be a problem.

One thing I can't quite comprehend, though. You said you rebuilt a Bronco, but you can't figure out how to remove the spark plugs on your outboard? Seriously? Having worked on a few Evinrudes, and others, I've never found one where the plugs were difficult to access. I looked at the picture of your engine that you provided, and the plugs are RIGHT THERE. Pull off the wires and apply a wrench to the plug. Lefty loosey, okay?

 

@Siamese one thing I definitely learned was when you don't want to waste time or money it never hurts to get some advice from someone who has done it before!

 

So OP, have you found the problem?

 

Planning on digging into it this weekend. I'll update once I've made some progress!

 

So I spent some time working on the outboard and got my marina's tech to take a look at it. No issue putting in new spark plugs and cleaning out the carb. Still no good.

We traced the fuel line and it looks like fuel is going correctly into the carb, I need to find now if it is coming out of there correctly. It is still cranking and once it kicked once or twice like it was going to start but it didn't stay.

So now going to work on some of the advice from @RichH. The tech it was not getting a spark but I wasn't there when he checked so I'm going to confirm and then continue from there. Any thoughts overall given this data?

 

So a couple updates in this saga...

I went in and borrowed a carb from the same motor that a friend has (which is fully functional) and put it in there which got it to spark properly and compression was to spec. But still nothing. So it was cranking, sparking, compression was good, and fuel is going into the carb properly but still not actually running.

At this point I'm thinking about taking it off the boat and totally tearing it apart so I would love any suggestions for things to look out for.

...Also if anyone is selling an 8-15HP motor in the Tennessee area give me a holler!

 

How is the timing set on this motor?
Could it be off?
I've seen electronic ignition coils on small engines go bad, still have good spark but the timing is off so it wont run.

 

Having worked on many of these, when the engine just dies, all of the sudden, there are more things than just spark and fuel. If you have access to a flywheel puller, remove the fly wheel and check the key that aligns the fly wheel with the crank shaft. I've found many of them that have sheared, thereby allowing the flywheel it to be misaligned. So you could get spark, but at the wrong time, thus the engine will not run at all. I've seen some so far out that flame blew out of the carb. This is not an uncommon problem with smaller outboards.

If you don't have access to a flywheel puller, DO NOT attempt to remove the flywheel by tapping it with a hammer. The flywheel is made of cast aluminum and can easily be damaged. Some tool rental places have outboard motor flywheel pullers for rent and a very cheap price.

When you remove the nut from the top of the flywheel, you should be able to see the flywheel key. If you can, and it appears to be aligned properly, then there is no reason to remove the flywheel.

If you have reasonable compression, there's a good chance the leaflet valves are fine. If not, and the engine has been run for extended periods at idle speed, those valves could be heavily carboned up, which could be the culprit as well. However, heavy carbon deposits on the valves usually result in lower than normal compression.

Hope this helps,

Gary

 

Is it possible that some salt buildup in the kill switch is sapping some spark. The older Hondas did this all the time.