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'78 merc tower of power starting/running issue

sloppyjoe

New member
I have a 1978 merc 1400 that I got from a friend a couple years ago. I've had it out on the lake ten or twelve times since I have had it. The problem I am having is that it's very hard to start. The only way I can get it started is by using the choke and using the throttle at the same time. Once it starts I have to leave the throttle open just a hair until it warms up. Which usually takes awhile. Even then it's very hard for it to take the fuel. Sometimes dies and has to be restarated and idled again for a few seconds. When it does take the fuel it's very sluggish at first like it's running too rich. Full throttle position only gets half throttle rpm. After a few more minutes it starts to pick up and really take off. It will then run really well for half an hour or so. Then as your going down the lake with it opened up really good it will fall on its face again for awhile and then pick back up in 5 minutes or so. It's like this all day with it. The boat had sit awhile before I got it and I replaced the needle valves n seats last summer. Any help would be greatly appreciated.
 
Sounds like the idle adjustments are way too lean. I suggest you tie the boat to a dock (or on the trailer) and readjust the carbs. (It's easier to do it that way.) When you get your best idle, open each 1/4 to 1/2 turn additionally.

Jeff
 
Sounds like the idle adjustments are way too lean. I suggest you tie the boat to a dock (or on the trailer) and readjust the carbs. (It's easier to do it that way.) When you get your best idle, open each 1/4 to 1/2 turn additionally.

Jeff

Thanks I'll try that as soon as I get some time and let you know how it goes.
 
sloppyjoe, While you are on the water,try pumping primer bulb to see if issue subsides,after readjusting carbs. Those adjustments are done in gear
 
sloppyjoe, While you are on the water,try pumping primer bulb to see if issue subsides,after readjusting carbs. Those adjustments are done in gear

Thanks for that info. This is my first boat. I have done alot of mechanic work on cars and bikes and things like that but never messed with boats. New territory for me.
 
I had the same problem. I adjusted the carbs. I think it was 2 1/2 turns. Then it ran great. U might have one carb flooding and one too lean..
 
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