my mercruiser I/O 1999 4.3L 190 H.P. starts fine when cold but starts when hot are difficult - 4 or more trys?

Answer 1

You are having a case of vapor locking. When the temp outside rises the engine compartment temps rise also, this makes vapor locking more common. A few things to try.
After a good run and you come off plane, turn the bilge blower on, let the engine idle for 2-3 minutes. This will allow you to get rid of some of the heat.
Try a different gas station, today most all fuels have up 10% ethanol the boils at a lower temp, approx 163 deg, than straight gas. Do not use 91 otc, it will not help.
Make sure you have the correct spark plug MR43LTS. To hot of plug will damage your motor, colder will not help.
Be sure your motor is running the correct water temp, 143 deg.
Last thing is to have the fuel system checked for a restriction. A shop can do this for you, or if you have the proper tools, I can advise you on how to check it.
Hope this helps

Answer 2

Sounds like flooding. Caused by choke set wrong. After running and getting hot. before starting motor again , remove cover and have someone hold the choke open. try starting this will let less fuel in carburetor and more air. It is normally in the open position when running. A closed choke is for starting a cold motor.

Answer 3

Could be the choke - but can also be an age old problem - vapor lock. This can happen when the fuel line to the carb(s) gets to hot.

Once it is running, does it run fine - or is it a bit 'rough'...

Answer 4

Sometimes your battery is too weak to turn over a hot engine. Try to determine why it gets hot, maybe a plugged waterjacket?

Answer 5

Try partially choking off the intake air when starting hot, to trouble shoot choke.

Answer 6

the engine is getting very hot from the sun and you might want to check engine coolant or your sencores 4.3l v^ one of my friends had that prolbem

Answer 7

I believe you need to change the spark plugs to a hotter plug.

Answer 8

advanced to much?