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470 hard starting occ

L

lime4x4

Contributing Member
Working on a 1987 470 engine. Occ the engine will stall out. If i go to restart it cranks real slow like the battery is dead. The battery and starter are new. If it stalls and i wait a minute it will crank over at normal speed. Any ideas?
 
Occ the engine will stall out. If i go to restart it cranks real slow like the battery is dead.
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If it stalls and i wait a minute it will crank over at normal speed.
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The battery...are new
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If the engine still has the 34 yr. old OE charging system, OB stator/water cooled regulator, it may not be charging sufficiently thereby forcing the new battery to provide more of the ignition power than the stator puts out which causes the battery voltage/amps. to drop, the engine stalls and cranks slowly unless you wait a minute which gives the new battery time to rejuvenate itself just enough to crank over at normal speed. Just a WA theory.

Dump the OE charging system and install a single wire Delco 65 amp alternator and bracket kit.
 
First, check all your wire connections very thoroughly,especially main grounds and the like. How long are your main battery leads from battery to starter lug and what gauge are they? How did you set your timing? You need to use a timing light. No way you can do it by ear. You probably already know this but figured I would mention it. It takes quite a bit of amperage to turn over a 470 with the delco starter. By the way, the originals are better than the replacement afermarket starters if rebuilt properly. Do you still have the factory water cooled voltage regulator? If so, get rid of all that nonsense along with the rectifier (generator inside front harmonic balancer). Buy an aftermarket alternator kit of some sort. Are you sure your key switch is good and you are getting proper voltage to starter solenoid. Could be alot of things so I figured I would get you started with these first. I have a 1988 3.7lx 180hp that I have recently rebuilt with virtually every upgrade imaginable. Just cause the starter is new doesn't mean it works. I bought the aftermarket alternator kit and the alternator had to be repaired by a shop because it was defective. So, is the starter that you bought an Argo or something similar? My Delco starter turned the engine really slowly when I first got engine and I carefully took it apart cleaned everything up real good and it has been working properly since. all the best, Tom
 
Motor was converted to a single wire 105 amp alternator. The battery wires from the battery to starter is just over 2 foot. Ignition was converted over to electronic. I set the timing to 4 deg before with a timing light. I know the carb needs to be rebuilt fore the stalling issue. Not sure which type of starter i have. It was new when i bought the boat.
 
The 470 / 170 was and is notorious for hard starting.

Got a few minutes ? Pull all the plugs and crank it, does it crank faster ? See any water shooting out the holes ?

The plugs they look " Steamed clean " ?

Spark Plugs < Click here for how to read the plugs.

When does the boat conk out, precisely ? When you give it gas or when your pulling back on the gas ? What rpm or is it at idle when your just pulling away from a dead stand still ?

When?

That should not be happening.
 
No signs of water in the cylinders. Usually conks out when accelerating . We use the boat for crabbing. If i go to floor it it sputters then dies or if i have to get the boat to turn a certain direction and i punch it. Accelerator pump is bad
 
Didn't get a chance to mention the exaust water shutter. That is important so as not to get water in the cylinders and can also cause blockage in drive as well which can cause overheat issues etc. Pretty sure you have an aftermarket starter and I read a few posts on another site about how the replacements are not very good. That is why I mentioned the OEM Delco starter with built in solenoid. I am almost positive that is what your engine would have been equipped with originally. (1987-1989) The original Delco would also have a support bracket that holds starter to lower block? Before you go and buy a rebuild kit or rebuilt carb maybe check fuel pump pressure (should be 4-6 pounds with the Carter mechanical pump). Also, make sure the spacer has been installed between fuel pump and block. If not, pump will create alot more than 6 pounds and engine will not run right. How old is the fuel pump? Did you clean the screen going into carb. (I am not sure if the mercarbs had a screen cause I have the Rochester Quadrajet.) But I am pretty sure it should have some sort of screen at the base of carb fuel inlet. The fuel pump was originally a Carter and can be purchased new at ebasicpower.com. You said the accelerator pump was bad! Are you sure the linkages are moving correctly when accelerating? It can be bent or straightened to adjust throw. Have you had distributor out of your engine? Maybe the timing advance weights need to be cleaned up or a spring is broken etc. Just trying to narrow down any possibilities before you go and spend money. Can't think of anything else at the moment. I had a similar issue and was lucky enough to have a spare carb for my motor and it is running great again. best of luck, Tom
 
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