1983 150 black max hesitation while getting on plane..possible culprit?

[mercdblackmaxx]

I have had this motor for a couple years now and havent had any problems with it at all. compression is even at 120 across the board. from a stop to getting on plane it seems to hesitate a bit when i punch it then once i get higher up on rpm it starts to smooth out and is almost like it shifts into another gear (i kno it isnt lol) other than this small issue its been a otherwise perfect 30 yr old o/b. am i nitpicking? i dont pull skiiers or anything so its not a big deal but i would still like to kno what could be causing this. i thought maybe i was overpropped but im only turning a 14x19 black maxx stocker and hit 6000 at wot. any ideas?

[rgsauger]

If you haven't done it in a while, especially with today's CRAP gas, time to rebuild the carbs and also to make sure that all fuel lines on your motor and in your boat are swapped for the new ethanol compliant ones. And, a new set of NGK plugs would probably be nice for it too. Sounds like its loading up and then starting to burn things off and "shift" so to speak, probably fouling a plug and then getting it back. Just some ideas...

[toyomirage02]

when it feels a lil hesitent bump the choke in if she picks up time for a carb job

[rev.ronnie]

Welcome aboard!

Agree, carb cleaning time!

Also, do a search for "black max" on here...... :) you may want to change your screen name and never say "black max" again. Guys will pick on you like the poorly dressed new kid at a fancy school.

[rgsauger]

Welcome aboard!

Agree, carb cleaning time!

Also, do a search for "black max" on here...... :) you may want to change your screen name and never say "black max" again. Guys will pick on you like the poorly dressed new kid at a fancy school.

Rev, surely that would never happen on this honorable and esteemed forum!!!! I can't believe that you would ever insinuate such a thing! :nonod: :icon_bs::eek:


But...on the other hand...you might want to change your name just in case, dude! :D

[mercdblackmaxx]

lol gotta ask whats wrong with using the term "black max" ? what is involved with a "carb job" ? ive got some mechanical know how and shallow pockets, what r the chances i can do it myself? thanks for the replies, welcome, and advice lol

[rev.ronnie]

"black max" is just commonly associated with real rookie boaters, no offense. Guys get quite a ribbing around here when seeking advise on their "black max"..

As far as the carbs, pull the air box and work you way back to the carbs, removing and cleaning each one. Take all the jets out, clean and blow out the passages, and replace needles/seats and gaskets if required. I would probably use this time to replace all the fuel line as well, with ethanol safe fuel line. You will need actual fuel line tie wraps to clamp them back on with. They are designed for fuel lines and have an rounded locking end. if you have oil injection, replace you pump lines as well. Cheap insurance.

[mercdblackmaxx]

"black max" is just commonly associated with real rookie boaters, no offense. Guys get quite a ribbing around here when seeking advise on their "black max"..

As far as the carbs, pull the air box and work you way back to the carbs, removing and cleaning each one. Take all the jets out, clean and blow out the passages, and replace needles/seats and gaskets if required. I would probably use this time to replace all the fuel line as well, with ethanol safe fuel line. You will need actual fuel line tie wraps to clamp them back on with. They are designed for fuel lines and have an rounded locking end. if you have oil injection, replace you pump lines as well. Cheap insurance.

lol didnt kno that. not new to boating, just to having a fast/high performance boat as my last one was a 71 16ft crestliner with a 55hp chrysler boat anchor lol ill keep that in mind as i dont think i can change my name lol i will def go through the carbs when spring rolls around thanks for the advice! i have heard my problem can also be caused by a bad fuel pump? sounds possible to me but probably wont kno until i pull it all apart right?

[rev.ronnie]

If you have a bad pump, or weak one, it may come out of the water ok, but then fall flat once the bowls are empty and the pump can't keep up.
I would suggest rebuilding that as well. the new kits are not the rubber flappers, but rather plastic. The ethanol doesn't shrivel them up like the old style ones.

And easy way to check to see if it's the pump is to have a passenger squeeze the primer bulb as you punch it. If it jumps and goes, you are on to a pump issue.

Make sure your vent is clear too.

[rgsauger]

As Rev said, replace all fuel lines from tank to motor and on your motor too. I just bought gasket kits and new float needles and seats. Cost me right at $100 total for three carbs worth. Takes 2-3 hours max to do. Well under a 6 pack! You need a new fuel filter, too. Last thing, new NGK's and make sure that your plug wires are sound and not rubbing against anything.

[rgsauger]

Oh, the fuel pump kit is like $25 or so. Use merc oem, not sierra. And, ditch your oil injection and premix at 50:1.

[mercdblackmaxx]

As Rev said, replace all fuel lines from tank to motor and on your motor too. I just bought gasket kits and new float needles and seats. Cost me right at $100 total for three carbs worth. Takes 2-3 hours max to do. Well under a 6 pack! You need a new fuel filter, too. Last thing, new NGK's and make sure that your plug wires are sound and not rubbing against anything.

all lines to the motor are new but i will def get new ones for on the motor. got new ngk's at the end of last season! and that sounds good about the cost and time to do the carbs thanks! will definatelty check all of the plug wires but if i rememeber correctly they were all in good shape. no oil injection to get rid of thankfully! thanks everyone for your replies its greatly appreciated and im sure is going to save me alot of $ and headaches in the future. cheers!