1995 115HP 2 stroke engine will not restart after warming up

[ESS54]

I have a C115 Yamaha outboard, 1995. It will cold start pretty easily but after running for 20 - 30 minutes, and being off for 25 - 30 minutes it will not restart.

I have changed all four plugs
I have replaced the fuel water separator
Battery is OK and carries a charge
When running it runs fine, accelerates does not stutter, runs well
It will restart IMMEDIATELY after shutting off.
It will restart after sitting for a pretty long time.
I have replaced the hoses from the tank to the engine.
I have not replaced the bulb but during a restart the bulb is firm.

Thoughts will be greatly appreciated.

Ethan

 

[MH Hawker]

when it wont start dose it have spark

 

[99yam40]

measuring the inputs and out puts of CDI while the no start happens will lead you to the problem if there is no spark
Use the proper test equipment as the service manual call for to compare the voltages to the spec

 

[ESS54]

Bit of a newb on somethings. What is the easiest way to check for spark? Thanks.

 

[99yam40]

a timing light or a spark tester works well to check for spark
Best is a spark tester that you can adjust the gap on and hook up to all plug wires at the same time.

You can make a simple spark tester with a board, nails, and wire
do some searching on the web

 

[ESS54]

Spark plugs appear to be getting spark. Did this by myself so I could not check all plugs and be 100% sure (I was cranking the engine and trying to look at the tester). Any reason the plugs would not spark after starting the motor and running for awhile. The engine will restart just fine after running for 15 minutes then sitting fro 2. But when it sits for 30 minutes it just won't restart.

I've replaced the plugs, water filter and bulb.

Also, I noticed yesterday oil coming out of the exhaust/propeller area. Picture of that is below. Thoughts on that?

 

[99yam40]

Might check the recirculation check valves to make sure they are still functioning.
]I just found 3 of the 4 on my C40 bad.
But it still fires up fine.

Have you pumped the primer to make sure the carbs or VST is still full at restart to see if that makes a difference?

 

[ESS54]

Might check the recirculation check valves to make sure they are still functioning.
]I just found 3 of the 4 on my C40 bad.
But it still fires up fine.

Have you pumped the primer to make sure the carbs or VST is still full at restart to see if that makes a difference?

After waiting 30 minutes I tried restarting with no choke or moving the lever up (this has worked in the past). I checked the primer bulb to see if it was firm, it was, I checked to make sure the primer was getting gas to the motor (the fuel filter in the motor showed gas coming in). I choked it and moved the lever up.

I have looked on line and youtube but cant seem to find something that shows me how to service the recirculation valves on this motor, a 1995 115HP 2 Stroke Yamaha.

 

[Silvertip]

Your engine is a two-stroke. Some oily residue may appear in the exhaust. Ignition components can degrade due to heat and/or age and simply become heat sensitive. If you plan to work on this engine yourself, buy a "Yamaha" service manual. It will save you time, money, frustration and more importantly, headaches and computer time searching for answers.

 

[99yam40]

I have looked on line and youtube but cant seem to find something that shows me how to service the recirculation valves on this motor, a 1995 115HP 2 Stroke Yamaha.

Apearently your motor does not have them like on the 3 cylinder motors
Did see only one check valve in the crankcase, but not sure how that would be tested without motor taken apart. so forget what I said