My TB V is similar to your MPI as it only does the long spark delay when engine is cold then once engine is warm it fires up right away. There is no ECM on my set up so it must be the TB V doing it.
Is there a sensor on the side of the engine that sends a RPM/Tach signal to the TB V? If so...
I have the 3-wire.
I was having sporadic no-spark issues
So replaced the following parts
-Spark Plugs
-Coil (this was the ittermitant culprit)
-Distributor Cap & Rotor
-Rotor position sensor (3-wire) in Distributor
That is how I noticed the long spark delay when starting.
The engine has done...
Here is the sticker on the top of my engine
You can see Merc is calling for AC 41-101 Iridium plugs gapped to 0.060
This is what they installed at the factory in 2010
I installed NGK TR6 Nickel plugs
they came factory gapped to 0.039" but I regapped them to 0.045
per Mercury Service Manual #25 for GM V-6 262 CID (4.5L)
Pulled the Original Factory Installed spark plugs and found AC DELCO p/n 41-101 The plugs look fouled with black carbon from running too hot/lean
These plugs have the following attributes:
Iridium
Heat Range =4
4k-7.5k ohms resistor
Gap 0.060
Socket 5/8 (16mm)
Reach 0.68 in (17.5mm) short...
Yes this is what I am thinking.
I am leaning toward the thermostat as the culprit... as plugs basically all do the same thing. But I am looking for someone with experience to weigh in to verify.
Just to be clear .. my boat runs great and even turns off now when I want it off. There is no more run-on issue. I am asking if the changes I made would reduce my performance.
The performance loss I am experiencing since changing plugs/thermostat i is very minimal but noticeable:
-Boat does not...
The TKS carb has an automatic choke system.
I am using a timing gun to watch for spark.
It is very consistent in the way it starts.. I have to hold the starter on for 4-5 seconds.. as soon as the ignition sends the spark the engine fires up right away.
No
I did not touch the mixture screw on the carb.
I just backed off the "idle speed screw" ("A" in picture below) on the linkage to lower the idle RPMs
I have a 2010 Mercruiser 4.3 TKS with Alpha Sterndrive V6 with 2 BBL Carb and Thunderbolt V Ignition (Engine s/n 1A612644) that has problems with run on.
I read through Mercrusier Service Bulletin 97-17 "Engine Dieseling or Running-On" and have made the following changes to my set up in this...
