This is a question for Dave or the good Dr or anyone else that might know. Would it hurt anything to hook up 2 batteries in series (at 12 volts) for more amperage for starting. Will it hurt the charging system or the starter on a 1977 Merc 1150? I have replaced the rectifier with a newer voltage regulator/rectifier.
If you're having trouble with the engine cranking slow, and it's not connections or starter solenoid, very possible the starter is the issue.
If the engine isn't firing off quick, check your choke shutters and make sure they're closing fully when the choke is activated.
Doc has had much success adding a priming system to the older Inlines, similar to what later models have. With a primer valve squirting fuel directly behind the throttle plate, they light off almost instantly. This eliminates the choke shutters completely.
The reason for my question was when it is a cold start it has to crank for a little bit before it fires. Once it warmed up it pops right off as soon as I hit the key. I was thinking if the starter would spin a little faster it would help. I will look into how well the choke is working and go from there. Maybe I will try pumping the primer bulb harder. Thanks for the help.
I agree, one good battery is all you need to spin the engine.......assuming your starter is good.
Remember, that engine has a stator with high & low speed windings.. A bad low speed winding will make hard starting, especially when cold.
BTW, 2 12 volt batteries in series will give you 24 volts.
2 12 volt batteries in parallel will you 12 volts.
All the old Inlines I've run like a pumped-up bulb (very hard), full Fast-Idle, and full choke until it starts. Shouldn't have to crank for more than 5 seconds to get 'er to pop off. If cranking for 10 seconds or more, there may be issues. The primer mod is a extremely effective way of getting them to pop off almost immediately.
Another mod that's not too complicated to do and might work well, the bottom carb on 99-c.i. Sixes isn't choked. You could easily add the linkage and choke shutter assy to the 3rd carb and that'll give you more choke action.
My old 1350, anytime it was cranky and didn't want to start, I thought maybe I flooded it. Invariably, it wanted more fuel, more choke, more fast idle. Never did flood it!! Of course it was drinking almost 14 gph at full throttle, on my old 15-SS Sidewinder ski boat!
That was back in the 80's, when we didn't think anything of burning 12 gallons water skiing on the weekends. Couldn't afford to do that, nowadays!
Thanks for the info. I meant to say parallel on the batteries. What I need is more fuel for the cold starts. I pump it until it is hard and even trim the motor in almost all the way in (which seems to help a little). I guess I need to come up with a way to give it a squirt of gas to help with the cold starts.