Hard Starting 200hp Merc..Why?

[Saukie]

Last two times out this week my 200hp merc has not fired right up....Just yesterday I replaced plugs, (feel good cure) and also my batteries have at best 50% charge..but it has always start before...QUESTION is..if a battery is 50% charge does the cranking amps drop by the same %..I also put new bateries in but yet to test this...what else can it be before I pay $$$ to solve a simple issue

[DK]

saukie, has any body been playing around with the idle adjustment?

[Vinny]

Check voltage during cranking. At 50%, when cranking (high load operation), you have a lower voltage available for your ignition system and therefore, a weaker spark.

[FishinMission]

Try this site
www.Iboats.com/forums/boat_engines/

Post your problem, or try searching the bulletin board. Do you have a manual??

[Saukie]

Thanks for the input...I just took the old batteries to Sears for testing...under load test they produced 10.58 volts & are rated new as 500 CCA, Alumaweld told me I need atleast 750 CCA for starting...However...I have been hitting the choke several times...after waiting a few minutes after cranking away then it will start...new to this motor I have not found the "sweet spot" on how to start it..after it starts no problems...I am somewhat confused at this point...thinking of not hitting the choke when I start..and with 750 CCA should fit up...

[Pilar]

Saukie, hard starting of a 'cold' motor is almost always related to fuel supply. Specifically the choke. I'm guessing here but your choke is probably electrically activated. If your battery is weak there may not be enough voltage to pull the choke in all the way while you crank it. You said that it starts fine after that. The warmed up engine does not require a full choke for starting. And it cranks easier since it is hardest to crank (drawing max amps and causing max battery voltage drop) when stone cold.

You can test this theory by holding the choke on manually while cranking it. If it fires right up then you have found the problem. As was suggested earlier in this thread, buy a manual.

Also talk to the marina or store where you bought the motor. You may not be the only person having this particular problem.

The last thing is to pay attention to your battery problem. If they are not staying fully charged then you have some other problems. I have found that prolonged anchor fishing kills my batteries. The run is short and the batteries power the radio and fish finder all day while anchored. For this reason I use two batteries. The cranking battery has only the starter on it and the other is a huge deep cycle that runs everything else. Add a 2 point battery switch and the rig is complete.

Even with this setup, I have to do an overnight charge of the deep cycle battery every couple of weeks. The boat never runs long enough to charge it back up. Realize that it can take up to 24 hours to recharge a deep cycle battery to 100% capacity.

Last of all to answer your question about partially charged batteries. As you discharge the battery, its ability to hold 12 volts output is diminished. At full charge the battery will hold 12.5 volts under load for a long time. A 50% battery will drop off to 11 volts or less under load very quickly. A battery that drops to less than 10.5 volts under load is considered to be completely discharged. The current delivered is diminished also. Same load, less voltage, therefore less current. It is a simple ratio. At 10.5 volts your 500CCA battery will only deliver ~440 amps.

Just get in the habit of watering and overnight charging boat batteries on a regular basis. Especially when stored for long periods of time. They will last much longer if you treat them this way.

Good luck!

[ 09-12-2001: Message edited by: Pilar ]

[Saukie]

Thanks folks....Manuals..yes going to Fishermans tonight to get "after market book"...also called Alumaweld service....to ask on proper starting seq ....I am told...push the key choke in and hold for 3-6 sec, release (We should do more of that), turn key..should start..if not, push in choke once more....then turn key..Will try at O'Dark Thirty Thur AM....with new plugs, batteries & this it should work...I think, and can not fully recall, but last times I have started it, the ramps have been packed, under pressure to get underway, I may have muffed it...by going choke crazy, thus flooding it....AGAIN THANKS ALL!!!!!!

[FishinMission]

One other thing....If you DO flood it, the excess gas will evaporate quicker if you hold the throttle wide open for a few minutes. Also...with cars too....starting with the throttle wide open will help. BUT....be sure you're outta gear, so if it starts you don't go flying!!! [img]images/icons/shocked.gif[/img]