What is the main cause of an outboard that's hard to start again after it's already warm

[909]

What's the cause?

It's on a 1998 Johnson 9.9

Is it usually plug related ?

 

[Scott Danforth]

Usually lack of maintenance

 

[CaptnKingfisher]

What's the cause?

It's on a 1998 Johnson 9.9

Is it usually plug related ?

 

[jimmbo]

Could be a Heat problem in Ignition System, or a high Fuel Level causing flooding. Todays crappy Gasolines are refined for FI systems where the fuel is under pressure in the lines, but it might flash too easily in a carb where the Air Pressure on it is Atmospheric which is lower, especially if warm, like after being shut down with engine hot

 

[racerone]

Motor needs 4 things to run. ---Fuel.---Crankcase compression.-----Cylinder compression.-----Spark at the right time.----Simple trouble shooting finds where the issue is.

 

[909]

Thanks for your replies.

I checked the spark. It was questionable. Sometimes would , sometimes wouldn't . Changed the CDI and Coils from a known working motor. Still hard to start.

Bought brand new plugs. Still hard to start.

How do I check for high fuel level

 

[racerone]

Changing parts can be an expensive way to fix a motor.----Many years ago I determined that many folks have trouble with their small engines.-----Simply because they are not using the right procedure for starting.

 

[909]

I have 8 outboards with interchangeable parts. They all start the same, with exception to this one. There parts are there, and free to swap, minus a little labor, with exception to new plugs. I figured this way it's a process of elimination.

 

[jimmbo]

You need to verify that the Spark can jump a 7'16" gap repeatedly. If it can't then there is a Problem. Check all connections, and grounds, including those to the engine block

This one is a long shot, but it can cause Difficulty in starting. A bad Crankshaft Seal under the Flywheel.

 

[909]

Thanks. I don't have a flyweel puller yet. I'll buy one. Can't fix what you can't see.

Since I swapped all the wiring, new plugs, new CDI , new coils, and also installed them myself, I'm certain the installation, connections and grounds are good.

Leroy's mentions:
Carburetor Timing : If you are having problems getting the motor to run as you think it should, possibly where the timing plate is considerably advanced, you may consider doing a "Link and Sync" of the carburetor throttle arm roller to the timing plate cam.

The throttle cam plate that rotates under the flywheel when you twist the twist grip and the plate has an raised line type mark on the front of it. This mark needs to be timed so that when you advance the throttle twist grip, that the carburetor roller is at this mark when the carburetor throttle shaft just STARTS to turn open.

Is this simple to do ? Is it just a matter of adjusting the throttle position. What's the process.

A friend also suggested something might be bad, or burnt under the flywheel. I need that puller asap.