2.4 HP engine chugs on take off

[illMATTic]

i got a mid 80's 2.4 HP engine. it chugs pretty hard upon take off unless i floor it. if i give it half or less throttle it will studder/chug. it is the same if i am coming off plane. if i ease out of it, it will chug until i let all the way off. other than this it runs like a top.

i dont think its being overloaded. i only have a 21P prop and the boat weighs around 1300#.

could it be a timing issue? advance?

[illMATTic]

i forgot to mention this is is an EFI motor.

[illMATTic]

one more try........

[T-REX]

Sounds like a TPI.......Tha reeson I say that iz kuz U said if ya nail it, it don't do it........Like a carb that haz a leen off idle, it wull bog or"Chug" untill ya pass the leen spot....Maybe the TPI iz not work'in properly........

Ther are a million other reasons that will cause a stumble, or "Chug", but it'z kinna impossible to do anythang but quess witout hands on time....:thumbsup:

[HydrostreamVector4m]

My guess would be a stater.
I would be to beleave your low speed windings are gone to lunch..

I had the same thing happen 2 years ago with a 2.4 200 and mind was the high side was out..
I Changed the stater and see ran great...

Hope this helps ya out.

[pyro]

TPI out of whack would make sense, since it only affects low and midrange fuel delivery, and not WOT mix. Do you know how to test it? I've outlined the procedure a few times. I used to own a 2.4 200 EFI.

[illMATTic]

will there be any harm in running it like this for a bit until i get it figured out?

[pyro]

As long as it isn't LEAN within the affected range.
Why ask about it if you're not intent on fixing it? :confused:

You'll need two strands of copper wire, a volt meter, a screwdriver and 10 minutes of your time.

[illMATTic]

i was under the impression it had to be replaced. i havnt been able to get to the boat since i posted these questions. ill do a search for your how to and get it adjusted. ;)

edit - ill check the voltage first before i rule anything out. i am getting smarter by the hour.

[illMATTic]

ok i checked the voltage. its at .25v at idle and runs up smoothly to 1.98v at wot. what should it be at idle and mid? this is an '85 2.4 efi updraft motor.

[pyro]

Sorry, I thought you had a Laser 200/220. I'm not sure what the correct values are for your motor. Time to get a service manual... ;)

[illMATTic]

i have already posted in the wanted section.

what are the values for your 90?

[pyro]

The stock late model BP EFI's have a vacuum TPI box.

Mine doesn't have one anymore, it has a Brucato PCU. :D No worries here!

[illMATTic]

i am thinking i am running a bit rich since i have read the 2.4 lasers are to be set at .135 and the 2.5's are set at .25 volts. im above both.

plus my prop is all sooted up. and i mean black.


any tips on where to find a manual?

[pyro]

2.4 lasers also read 7+ volts across the TPI at WFO.

[ASTROCRAZY]

I have the same motor & would also like to know what it should be set at. I got the Mercury manual that mercury racing told me to get according to my serial # but it covers the later 2.4's with the vacuum TPI & not the manual ones. :nonod: What direction should we go now ?

Jeff