Almost started! but wont. 71 merc 800 (video)

rtpassini

Chief Petty Officer
Joined
Nov 27, 2008
Messages
508
I almost got it running. closer than it has yet.

but now theres a new problem. the video pretty much explains it all. the buzzing at the end is my g/f still holding the key. starter is brand new (should be the right one) and 90% of the wiring is new (should be all correct)

http://www.youtube.com/watch?v=5BhWgoojaPI
 

Yepblaze

Lieutenant Commander
Joined
Jun 1, 2001
Messages
1,686
Re: Almost started! but wont. 71 merc 800 (video)

Try a different battery. Like the one in your car. A good cranking battery.
 

rtpassini

Chief Petty Officer
Joined
Nov 27, 2008
Messages
508
Re: Almost started! but wont. 71 merc 800 (video)

the battery should be good to go. i had it charging since yesterday afternoon.

when it sounds like its about to turn over, it seems like the starter stops spinning? does that seem like a correct assumption? and it just makes that buzzing noise?

every other time i tried working on i and starting it, it would spin the flywheel constant, except now that its starting to turn over it wont...
 

Scoots

Cadet
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Apr 11, 2009
Messages
29
Re: Almost started! but wont. 71 merc 800 (video)

It sounds like you either have a weak battery or a poor ground. I used to have a little Chevy S-10 and the starter did the same thing. I installed a new ground and it started right up. Your starter should be spinning until you stop turning the key. It appears that it is spinning, but, not enought to throw the bendix up to engage with the flywheel.
 

sschefer

Rear Admiral
Joined
Nov 13, 2008
Messages
4,530
Re: Almost started! but wont. 71 merc 800 (video)

Mine did the same thing. Without the plugs in it will turn over fine but with the plugs in, the starter disengages prematurely. Mine turned out to be a timing issue.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,082
Re: Almost started! but wont. 71 merc 800 (video)

RT- You need the starter to turn the motor about 300RPM, plus a minimum of 11VDC on the white and red wires on the switchbox, for that motor to have proper ignition, and a chance to start. You might check the voltage at the switchbox, and estimate the cranking speed.
 

rtpassini

Chief Petty Officer
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Nov 27, 2008
Messages
508
Re: Almost started! but wont. 71 merc 800 (video)

Well, I got the motor to start!
i just had to keep trying for those short spurts of starting.

If the primer bulb isnt hard and the warm up lever isnt up, it seems to spin the flywheel constantly (starter doesnt stop like in video)

just kind of strange why it does it like that...but i havent tried anything since i started it and ran for 15-20 seconds. noticed it wasnt peeing from the tell tale. is this normal with muffs on?
 

MERCrazy

Cadet
Joined
May 25, 2009
Messages
11
Re: Almost started! but wont. 71 merc 800 (video)

as the engine begins to run on its own power the starter gear disengages...
you say ( it spins fine when the bulb is not hard ) no fuel = no start.... so it keeps trying till the motor runs on its own power even if for a moment .... just enough to disengage the gear !
 

Moody Blue

Captain
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May 24, 2004
Messages
3,136
Re: Almost started! but wont. 71 merc 800 (video)

These old motors NEED lots of fuel to get started. Almost impossible to flood them, so prime till bulb is hard, choke on, and fast idle lever about 1/2 way up to start.

The flywheel kicks the starter gear down once the motor RPM exceeds the starter RPM, that's why the starter disengages in your video. Without priming the fuel system and no fast idle, the motor has no hope of starting so the starter just spins the flywheel till the battery runs down or you burn up the starter.

Have you performed the sync and link procedure? If not, you are fighting a loosing battle.

It is "typical" when on muffs for the tell tale to not show much water. Before I changed the water pump I had no flow from the tell tale at idle on the muffs. With a brand new impeller, I get a trickle of water at idle and a weak stream at about 1500 rpm. Let the motor run for about a minute and feel the temp of the exhaust cover with your hand. If should be cool to cold if the pump is pumping sufficient water to the motor. If it is warm or hot then the pump is shot.

For the small cost and piece of mind I would make it a priority to change it, especially if you don't know the last time it was done.
 

rtpassini

Chief Petty Officer
Joined
Nov 27, 2008
Messages
508
Re: Almost started! but wont. 71 merc 800 (video)

dumb question. but...wheres the exhaust cover? haha
 

Moody Blue

Captain
Joined
May 24, 2004
Messages
3,136
Re: Almost started! but wont. 71 merc 800 (video)

Pull the clamshell cowling off. The exhaust cover is on the port side of the motor nearer the back of the motor. Its a large smooth plate that runs the full height of the block.
 
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