mercruiser 3.0l 135hp cutting out.

hi
have the merc 3.0l which cuts out after about 10 mins high speed.then doesnt start.will start later after an hour or so but its a struggle.as soon as i take out of water with muffs on it starts first time.
Any suggestions? could it be the coil?
Regards
Jon

 

re:

Could be the coil, when it cuts out easy to check to see if you still have spark. Could also be vapor lock. Check your fuel line routing to make sure it isn't getting too hot causing the fuel to vaporize before it gets to the carb. If you are fuel injected, maybe a weak fuel pump

 

thanks ken will try

 

Fuel tank breather

 

hi
renewed the fuel line ,went out same problem.checked for spark and it was sparking very strong but will not start yet again!!!arrrr!!!!took out of water and started first time???any ideas guys?
regards
jon

 

The muffs are connected to a hose, correct? So you are getting cooling flow then. Are you sure you are getting cooling flow when in the water? Is the impeller functioning?

 

What does the temperature gauge show? Those engines went through several redesigns on the thermostat housing and exhaust manifold. They sometimes start overheating after some time. Does it have a small water bypass hose between the housind and the manifold behind the carburetor?

 

hi
temp is fine .checked distributor and found the coil pickup for solonoid corroded .maybe when hot is starting to fail and when cools starts because contacts in coil pickup join again.
need these parts guys but struggling,live in uk and also need a fuel line from fuel pump to carb.any contacts would be great!
cheers
jon

 

The fuel line you can make with steel brake line and a flare tool. There are many online marine suppliers that can ship the ignition parts .

 

cheers gonzo.found place in u.s.a .saved 60 pound by cutting out uk middle man.RESULT!!!

 

Ooh thats a bit small for a fuel line. Too small.

135Hp@ 5 galls per 100HP used is about 7 galls per hour.

 

Fuel lines are 5/16" ID the same as a brake line. On bigger engines they may be 3/8" which ar also a common size for break lines.

 

On what? air brakes on trucks? Not hydraulic brake lines on cars.

 

Hydraulic lines on most any car has one of those two sizes or the metric equivalent.

 

Rubbish. Have a look before you post .

Brake pipes on a car will hardly be those dimensions OD.

5/16 ID???? never.