Merc 850 Hard starting after 30 min.

[cnccustom]

My 75 merc 850 starts fine in the morning before we go out and runs perfect all day till we shut it off for 30 -45 minutes or so to fish....then its hard to start...will not even try to start till I hit the choke then it tries to start and eventually will with choke.....also I noticed when its warm the bulb will not get hard,this could be normal not sure...bulb gets hard in the morning for first start up and after I get home for motor washing out...starts right up.......also when I am out if I shut if off for 5-10 minutes it fires right back up.........Thanks in Advance you guys are Great Prob solvers

 

[cnccustom]

Re: Merc 850 Hard starting after 30 min.

got to thinking and the time before last it was hard to start in the morning..acted the same way

well I will start by running some seafoam through it and see if that helps anything

 

[tashasdaddy]

Re: Merc 850 Hard starting after 30 min.

start with a compression check, and post back,

 

[Gold Bear]

Re: Merc 850 Hard starting after 30 min.

cnccustom,

Sounds like the carbs are just a bit lean. Try turing the idle mixture screws out (CCW) about 1/4 turn and see if that does the trick. Also, you may have the turn the idle speed screw in just a bit to re-establish the idle speed to the same RPM's it was before.

Good Luck,

Gold Bear 8)

 

[cnccustom]

Re: Merc 850 Hard starting after 30 min.

I don't have any thing to check compression but I just got it back from the shop last week and they said compression was fine...had a new trigger and distrubuter housing put on......when I bought the boat a month ago it just had 3yr service done but sat for 6 mos.

I have come to realize my problem is intermitent...sometimes cold in the morning it fires right up other times takes a while...sometimes after sitting an hour it will fire right back up and other times it won't

 

[tashasdaddy]

Re: Merc 850 Hard starting after 30 min.

cold inline staring procedure. pump bulb till hard, fast idle lever all the way up, hold choke, turn key turnover 5 times, and repeat. will have to play with choke to keep it running until it settles. inlines are gas hungry in the morning and when cold.

 

[cnccustom]

Re: Merc 850 Hard starting after 30 min.

ok...now should the bulb get hard during the day while out......I tried pumping it and it would not get hard out on the water when I had the problem...could it be a check valve problem in bulb?

 

[cnccustom]

Re: Merc 850 Hard starting after 30 min.

thanks for all the help........

 

[tashasdaddy]

Re: Merc 850 Hard starting after 30 min.

if the float and needle valve are working properly, when ever you pump it, it should get hard. all you are doing when pumping is filling the carbs, the the float should close the value and the bulb gets hard. if not getting hard the the valves are leaking.

 

[cnccustom]

Re: Merc 850 Hard starting after 30 min.

ended up being the bulb.....the check valve in bulb was not seating correctly and siphoning gas from carbs while sitting......all is well now ..thanks

also should add that out on the water I only pumped bulb a couple times...didn't want to flood it

 

[tashasdaddy]

Re: Merc 850 Hard starting after 30 min.

some times it's the simple things we over look. glad you running.