Alarm and lack of throttle response

[ktmahc]

1985 Mercury Black Max 150: Two things, 1st alarm sounds (steady beeping) after I was on lake. I turned off the master ON/OFF switch and it turned off the alarm. 2nd after trolling (idle seed) for 15 min went to go full throttle and wont take throttle past 2250 rpm without dieing. went through this trying over and over and am able to get the rpms to 3k then it will clear out and move out at 6000 rpms nicely. As long as I keep the rpms above 2500 I can throttle were ever I want. Let it go below or stop and take off, will probably do it again.

 

[Dukedog]

sounds like a stator went south but.....

after tha over temp (probably water pump stuff) ya need to do a comp test asap.. look at all tha plugs for any aluminum deposits.. get back here with what ya come up with....

 

[ktmahc]

UPDATE: Alarm was low oil alarm.... cap was loose. tightend cap and checked oil consumption and all is ok there. still low power after on the water for 2-3 min if trying to leave from idle. If i dont let it idle i can power around lake for as long as I dont let the rpms down to idle. Runs real nice at 6k if I can get past the mid throttle area.

 

[Dukedog]

sorry, I misunderstood what your buzzer was doin'.. thought you were sayin it was a steady alarm.. "beeping" didn't take when I read it!..
now think what ya may have carburetor, idle timing and/or bleed problem along with tha possibility of tha stator.. if this just started and hasn't been doin' it all along that will probably rule out tha timing part.. you can try this.. trim tha motor a tad positive with it idling.. if it improves any at all you probably need ta do tha carbs..

 

[ktmahc]

I have replaced the Stator, Trigger, Both control boxes and a rectifier. All these parts were out of spec. Not by much, but all out of range. Boat ran better but still the lack of power (being able to go full throttle). Rejetted carbs for altitude
(7500ft). still ran better again.... but not able to go full throttle.

Great people at Curt's boat supply in Colorado Springs Co. helped out. I showed a video to Curt and he looked at my boat and said my motor sat too low in the water. Raised up motor 2 holes. This is the origional motor/boat combo. The previous owner went out by himself. I had 5 people inthe boat. The boat runs like a stipped a$$ ape! The exhaust was being compromised. My understanding is that these Black Max motors had this issue! :first::joyous::joyous::joyous::lol:

 

[Dukedog]

My understanding is that these Black Max motors had this issue! :first::joyous::joyous::joyous::lol:

this "issue" starts with dealer and/or owner original motor (motor height, offset, prop combination) set up 99% of tha time......

 

[Texasmark]

I just had that experience. Bought an '02 Crestliner 1750 Fish Hawk (site and sales brochures available on the www) with a Merc 115, that was just serviced by the dealer's mechanic and compressions were 3 at 129 and 1 at 131...good to go there. Prop was a Ballistic 22XP.....that's 22" pitch on a 2:1 gearbox and that boat. Also it was jacked up in the 4th hole, transom mounted, no jack plate.

1st time out it wouldn't take throttle coming off the no wake buoys....just bogged. Took it home and did some tweaking. Prop slip calculator said that prop was wayyyy to much for that rig. Got her going by dropping engine down to 1 hole up (2nd hole), didn't go all the way down, works ok here, and dropped prop down to 17P....800 ft, just me, runs out just under 40 GPS, single digit hole shot; happy with that and let the setup alone.

Absolutely no idea as to what the PO had and was running and whether or not somebody at the dealership decided they needed the prop that was on it and swapped the 22 for it. No doubt he wasn't going anywhere with what was on it!

 

[ktmahc]

post is complete

 

[QBhoy]

Hi

you need to ditch that oil injection system ASAP and pre mix. This big V6 merc of that vintage is about the worst of them for failing. I learned the hard way. I’m amazed it’s still running that way. Honestly.