Mercruiser 4.3L Apha TKS Motor - Running Badly

trsail59

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Mar 21, 2019
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I have a 13 month old Mercruiser factory "Remanufactured" TKS Engine part number 865108RB9 when I plug it in to Mercs website it does'nt recognize it...looking for electrical schematic...

Ran okay yesterday in the morning but when I went to restart it...it seemed like it flooded and then would not fire and did not start. Today it started this morning and ran only on a few cylinders lots of blue smoke. Removed plugs most were badly fouled with carbon. With plug wire attached tested spark by holding the cleanest plug against a clean bolt on the exhaust manifold. Spark was intermitant and yellow.

Voltage to the coil dropped to about 10 volts during cranking. Checked coil resistance across low voltage posts .5 to .3 ohms. Infinite resistance between low voltage coil posts and high voltage output female plug. Checked coil to distributor cap high voltage wire reads infinite resistance... on my fluke 324 meter.

Choke plates did not open...could not disengage them...

My last boat I repowered with EFI wish I had with this...not a fan so far of TKS.

Please let me know how you think I should proceed to troubleshoot this issue.

Thanks for your input,
Tom
 

alldodge

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Mar 8, 2009
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42,611
Your not going to find a reman Merc motor at the Merc site.

Take the fuel filter off and dump in a clear container to see if there is anything but clean gas

It sounds like the carb is flooding, and if so its an easy enough fix. Remove top of the carb and check needle seat and float setting.

Wiring for TKS is in link
http://boatinfo.no/lib/mercruiser/manuals/mercruiser41.html#/0

Simplistic diagram is below
TKS V6 and V8 block diag.jpg
 

trsail59

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Mar 21, 2019
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Thank you for your reply and the information you provided...

You don't suspect I have any electrical issue....even with a weak erratic spark...?

Do you know where I might find the specs on the float setting for the carb?
 

alldodge

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You may or may not have a spark issue, suggest using a spark gap gauge. A plug is easy to use but most cases does not provide a clear indication

Do you know where I might find the specs on the float setting for the carb?

Yes, its in post 2 where its listed about wiring. Manual 41 is for the TKS which includes wiring, carb, adjustment and specs
 

trsail59

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Mar 21, 2019
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I guess I was in error when I said this is a TKS Motor the carb in the manual you refered me too does not look the same looks like a more standard carb...

Any ideas on where I might get some manuals for it...sorry fo the misinformation...I am pretty unfamiliar with the 4.3L engines...

Without a part number how do I identify the motor so I can purchase parts?
 
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