50hp 2stk hard start

peddler95

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Nov 25, 2009
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I've been fighting this problem for quite awhile now and think I may have found the problem but need confirmation.

Motor is hard to start first time out and runs rough for awhile after starting . Then runs great and starts quickly thru out the day of fishing. I had assumed it was a fuel issue with either the carbs not filling when primed or a malfunctioning prime start valve. Did the bench test on the prime start valve and it checks out ok. You can also hear it coming off fast idle a couple of minutes after the engine starts which leads me to believe that it is not the problem.

Carbs have been cleaned, new fuel line, bulb, and filter. I no longer think it is fuel related.

Since it only happens when the boat has set up for a week or two, I thought about a battery issue. Although it cranks ok I'm not sure it is giving a good enough spart to start cold and could be why it smokes (fouled plugs?) after starting.

Checked the battery voltage with a good digital meter = 12.3 volts no accessories on, 10.4 volts when cranking. Seems to me to be a large drop. Can anyone advise what the voltage when cranking should be? After it runs awhile and charges the battery it starts too fast to check the cranking voltage. I guess I could pull the stop lanyard and read it that way?

While I keep a charger on the trolling battery I have never put one on the starting battery. That should help by starting out with a fully charged battery but, especially if anyone agrees that this could be the problem, it may just be time for a new battery (three years plus old).
 

peddler95

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Nov 25, 2009
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Re: 50hp 2stk hard start

Thanks and my apology to everyone that may have read my post but, after studying the wiring diagram, it dawned on me that the sole purpose of the battery in the starting and running of the engine is to run the starter motor. The spark comes from the pulsar units. In theory, the engine should start with a dead battery, I realize it came with a rope for just this purpose but I, for one, am not about to try it. That's what I have Sea Tow for.
 

99yam40

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Sep 7, 2008
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Re: 50hp 2stk hard start

Tell us how you are trying to start the motor when cold.

A low battery will not spin the motor as fast, that could cause a problem
 

peddler95

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Nov 25, 2009
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Re: 50hp 2stk hard start

nothing special - pump up primer bulb fully, turn the key. no throttle. The first time out it will crank but show absolutly no indication of wanting to fire. The first time it finally "chugs" it will start in the next try or two. Some days it starts with about five seconds of cranking, but not often.

It sounds as if the starter is spinning as fast as when the battery is fully charged and, on the few times that it really takes a long time to start, there is no noticible slow down of the starter.

Other than being a pain, if I have to crank it several times to get it to start it oils up pretty good and really smokes while it warms up. I am assuming that the oil injection is pumping full bore when the starter is turning over even though the engine hasn't started yet??
 

99yam40

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Re: 50hp 2stk hard start

I think Prime Start motors do not normally start up on first turn of the key. My C40 usually fires up on the 2nd or 3rd 2 second turn of the key
 

peddler95

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Nov 25, 2009
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Re: 50hp 2stk hard start

Thanks - maybe it's something I just have to live with. Ethanol fuel doesn't help the situation either.

Do you think the two volt drop when cranking is normal?
 

99yam40

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Sep 7, 2008
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Re: 50hp 2stk hard start

it is easy to pull battery and have it tested. 2 sounds kind of high check all connections and clean
 
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