93 merc 150 blackmax

[Capt.Delo]

Hello All! Thanks for reading my post. I am in a pickle. I cant figure out why my outboard loses power at half throttle. My mechanic has already.
Swaped the stator, Checked compression on each cylinder all were about the same in the 110 range.Replaced both switchboxes and the trigger. Cleaned the carbs. the ball stays full and if i pump it it makes no difference. it turns out that cylinders 2 and 6 are not firing. and there is a blueish tint smoke coming from inside the cowling. I am going on vacation in 3 days to the keys and my boat is not ready. please any help would be appreciated!!!!
The engine is a 1993 merc 150 xl Blackmax V6 Carbuerated!!
Thanks,
Capt. DELO

 

[jmj120]

Re: 93 merc 150 blackmax

Could be the coils maybe??
You might could switch coils with a cylinder that is firing and see if the problem follows the coil. I've got a 1992 xr6 150 so I'll be interested in what you find out.

 

[Capt.Delo]

Re: 93 merc 150 blackmax

Sorry forgot to mention he changed the two that were not firing 2 and 6. (coils)

 

[jmj120]

Re: 93 merc 150 blackmax

hmmm. Did he install new power packs. A buddy of mine went thru a simular thing. Turns out he got a bad power pack. Brand new power pack out of the box was bad.
I don't know if the voltage regulator would effect this or not. From looking at mine, it looks like it has two of them. Maybe you could swap those??
I feel your pain.

 

[Capt.Delo]

Re: 93 merc 150 blackmax

Thx for your help JM. Switchbox powerpack... Same thing? dont know if they are not.

 

[Capt.Delo]

Re: 93 merc 150 blackmax

Just spoke with mechanic. says he restesetd the compression 100-115 on all 6 we are getting spark to all 6 and we are getting fuel. What am I missing here???? Gak in my fuel tank maybe sediment clogging the carbs?

 

[j_martin]

Re: 93 merc 150 blackmax

It doesn't take much to plug up the thumb sized fuel filter on that engine.

 

[sschefer]

Re: 93 merc 150 blackmax

Two things you need to check..

1. The choke solenoid. Make sure all the tubing is in good repair and that the solenoid valve is not leaking.

2. Bleeder circuits... Make sure that all the tubing is in good repair and test the check valves for proper operation. This is possibly the source of your blue smoke under the cowl.

Either one of these can cause your problem. I would not suspect them except for the fact that you've eliminated everything else..

FYI your compression is like factory new... The motor has compression reliefs in the exhaust porting that make it idle smooth as a kitten.

 

[jmj120]

Re: 93 merc 150 blackmax

Well, mine is doing the same thing, I'm cleaning the carbs and installing new gaskets. I'll let you know my results when my gaskets arrive and I finish.
Maybe your carbs are clogged??

 

[jmj120]

Re: 93 merc 150 blackmax

Looking back at your posts, I wonder if he's calling the regulator the "switching box" The power packs are on the side of the engine, mounted on top of each other. Would be on the side opposite the throttle linkage. (I'm port/starbord ignorant)

 

[j_martin]

Re: 93 merc 150 blackmax

Looking back at your posts, I wonder if he's calling the regulator the "switching box" The power packs are on the side of the engine, mounted on top of each other. Would be on the side opposite the throttle linkage. (I'm port/starbord ignorant)

On johnnyrudes they're power packs. On Merc's they're switchboxes.
They send the power to the coils for spark.

hope it helps
john

 

[Capt.Delo]

Re: 93 merc 150 blackmax

well. Apparently it was a combination of electrical things. mechanic put all new ignition system and runs like a raped ape now!!! I think it was the coil wires/coils.
Thank you all for your help and opinions Much respect!!!!
Now I am off to the keys to catch lots o fish for a week!!!
will let you know how it goes....