'72 merc hard to start..update

[monk-monk]

all right guys..she started..but not right away!! choke plates closed tight..idle lever straight up..turns over good w/ plent of spark. would not start until i took a squirt bottle and sprayed into the upper two carbs..fired right up..and i had better luck controlling cold motor idle pulling the manual choke about 5/8's in. up. continuosly taping the electric choke wasn't so successful. what do you think???

 

[emckelvy]

Re: '72 merc hard to start..update

I assume by "taping" you meant "tapping" the choke; note that you need to hold the choke button down continuously until the motor starts and runs smoothly. If it dies when you release the choke, it still needs choking.

You may also need more fast idle, you can try moving the lever farther than straight up. If the throttle cable isn't adjusted with the correct pre-load, sometimes you won't get sufficient travel even with the fast-idle lever all the way up.

You want to adjust the cable such that it has enough pressure to push the throttle lever on the motor into the idle stop; but not "mashing" it into the stop. Just enough so that when you throttle up, then back to idle, it returns to the stop consistently.

Another issue, you really need to get it in the water, warmed up and in gear, to be able to adjust idle speed and idle mixture. It may be you're too lean on the idle mixture and these motors don't like that, they get extremely cranky. Usually you have to run them on the rich side of the adjustment band for good cold starting and good throttle response out of the hole.

You could try adjusting the idle mix screws about 1/4 turn rich (CCW) and see if that helps.

Keep us posted.........ed

 

[Plainsman]

Re: '72 merc hard to start..update

Push the cold lever as far forward as it will go, hold the choke button in until it starts. If it starts to die, hold the choke in some more.

When you pump the bulb before you start it, is there fuel spilling out of any carbs?

 

[monk-monk]

Re: '72 merc hard to start..update

hey eric! no i did not see any fuel coming out and i looked for that because of what y'all said about "drooling". when i pumped the bulb i heard it filling something up like the crank case or something but, when it got tight finally, it seems i was unable to pump the bulb anymore. also though i had it tilted all the way back and on a little incline in the yard..but not excessive.

 

[Plainsman]

Re: '72 merc hard to start..update

It should be drooling fuel out of the carbs if you pumped it that much.
Have you rebuilt the fuel pump? Does the fuel tank have a vent that maybe is pluged? It just seems that your not getting enough fuel to the carbs to get it going.
Once you get it running does it stay running?

 

[timmathis]

Re: '72 merc hard to start..update

I know from doing so many times . It is a hassle and embarrassing at the landing having to pull the cover to get it started when cold. With a spray bottle, manual choke etc.
First try a good dose of seafoam in the fuel supply. It may surprise you!!! (Hey it has a money back guarantee)
Make sure the adjustment pin that stops the motor when trimmed all the way down is in the lowest setting. So it will set back as far as it can.
Fuel runs down hill if it is leaning forward it can run out the front of the carbs.
Like I said before give the bulb, After pumped up firm 2 or 3 slow firm pumps.
It does not have to be real hard pumps. So you don't have to worry about stretching the fuel pump diaphragm or blowing any seals Etc. I have done this for many years with marine motors with no problems at all.
With a little choke and play with the cold warm up lever and it should start right up.
If if don't start then you may have to pull and clean carb's and or troubleshoot the fuel system.
Good Luck, Tim

 

[monk-monk]

Re: '72 merc hard to start..update

no eric i have not rebuilt the fuel pump and i also have brand new gas tanks. once it is warm enough to take choke off it idles pretty smoothly at 800 rpm and i moved the idle lever forward to about 1050 rpms and still sounds smooth. these carbs seem to residually have a gas drip at the brass fittings at the carb body. not bad but i can wipe it and it will come back. i can't tell if its coming from the fittings or dripping down from above the fittings. and this is on all carbs same area.

 

[Plainsman]

Re: '72 merc hard to start..update

I'd listen to Tim, he has much more experience than I do. He has helped me many times in the past.

 

[monk-monk]

Re: '72 merc hard to start..update

tim, i'm going to do the water pump service this week as y'all directed me to do so, then this weekend i'm going to the lake put it in the water, run it and see how it does. you've mentioned about not running it lean. when i do this test run i'm going to warm it up, and work some throttle points,like run at a smooth rpm first to see if the fuel delivery keeps up or if it falls on its nose, if this does ok, i'm going to go for a holeshot to see if it bogs when i slam the throttle wide open. just my thoughts, i want your opinion on this first run. thanks for your patients

 

[timmathis]

Re: '72 merc hard to start..update

hey eric! no i did not see any fuel coming out and i looked for that because of what y'all said about "drooling". when i pumped the bulb i heard it filling something up like the crank case or something but, when it got tight finally, it seems i was unable to pump the bulb anymore. also though i had it tilted all the way back and on a little incline in the yard..but not excessive.

What you hear is the fuel flowing by the needle and seat. That is what you want to hear. If it don't start first time do it again. Don't worry you can't hardly flood a inline.