Mercruiser hard to start

[onthehunt49]

My 5.7 mercruiser, probably mid 90's year I think. Hard to start if sits a week, Have to use starter fluid of gas in carb to get to start. Once started, will start with turn of key all day or for a day or two. But let it sit a week or so. And same process over again.

Thanks

 

[Scott Danforth]

describe your starting process. you should not need to use ether

however in warmer temperatures, the fuel will evaporate from the carburetor thru the open vents and require the carb bowls to be refilled by cranking the engine over a few times to get fuel back in the carb

 

[onthehunt49]

describe your starting process. you should not need to use ether

however in warmer temperatures, the fuel will evaporate from the carburetor thru the open vents and require the carb bowls to be refilled by cranking the engine over a few times to get fuel back in the carb

I push throttle open all the way. Then push to1/4 and start cranking. Then I will pump few times and try again. Rare occasion it starts. Give a squirt of starting fluid to carb and starts up. From then on, just click of the key and it starts. Seems cold blooded at first.

I do live in South Carolina, so its hot and humid.

 

[ste80]

fuel pump is connected to the starter motor so it will start to pump fuell only when you start the motor and normally carbs get empty so need time to fully fill it. to avoid this i connected the pump with one switch on the boat board and i normally activate it before to start the engine. ( it won't work if you have oil low pressure as well)

another issue could be maybe related to the choke maybe it is not cloosing properly so too much air is going on the carbs in cold condition

try to pump with throtle 2 or 3 times before startup end reeduce the gas during switching on (less then 1/4) and check if the chke is cloosed in cold condition

 

[Scott Danforth]

I push throttle open all the way. Then push to1/4 and start cranking. Then I will pump few times and try again. Rare occasion it starts. Give a squirt of starting fluid to carb and starts up. From then on, just click of the key and it starts. Seems cold blooded at first.

I do live in South Carolina, so its hot and humid.

do this.

if it sits for a week. crank for 5 seconds.

then pump once fully, bring back to neutral, then advance to 1/4 throttle. then crank. it should fire a lot sooner.

give the pump a chance to fill the carb before you pump the throttle to prime the carb.

fuel pump is connected to the starter motor

fuel pump is operated off a cam lobe on the front of the cam that operates the fuel pump lever on the OP's mechanical fuel pump in his 90's boat.

 

[ste80]

do this.

if it sits for a week. crank for 5 seconds.

then pump once fully, bring back to neutral, then advance to 1/4 throttle. then crank. it should fire a lot sooner.

give the pump a chance to fill the carb before you pump the throttle to prime the carb.



fuel pump is operated off a cam lobe on the front of the cam that operates the fuel pump lever on the OP's mechanical fuel pump in his 90's boat.

Sorry i assume that he was working already with electric pump you are right