Black Max Piston Work

[GraAlaMat77]

I have a 1989 Black Max Xr4 150hp on my boat. The compression on the left side, middle cylinder is really really really off. It is due to the fact that the boat was run while the carb. was clogged up and fuel not reaching the cylinder. I was wondering what the average cost would be to bore out the cylinder and replace the piston, along with cleaning the carb. Also any other comments or suggestions?<br />- Thanks

 

[KCLOST]

Re: Black Max Piston Work

Man, that is a tough one...<br /><br />I could be due to a fuel+oil starvation problem but both middle cylinders feed off the same carb... So it "may" be something behind that carb!<br /><br />I really hope that you just have a blown head gasket that is preventing the full compression on that cylinder...<br /><br />You will really need to pull off the clinder head anyway to diagnose the damage if there is any...<br /><br />If you want to try that yourself, let us know... I recommend getting a manual, and we can also help you through it... It will be a fairly easy in regards to other things that could be wrong...<br /><br />What were the compression numbers? Have you looked into the cylinder with a scope or something yet? Did you have an overheat alarm?

 

[achris]

Re: Black Max Piston Work

KCLOST,<br /><br />I know that you are the specialist on these engines, and you are correct that each carb feed 2 cylinders. However, each carb is in fact 2 seperate throats, feeding one cylinder for each throat. Which cylinder depending on whether the reeds are horizontal or vertical. So, he could have gotten the fuel supply for one throat clogged up and just killed the cylinder that it feeds.<br /><br />GAM77,<br /><br />I don't know how the prices compare between Aust and USA, but I did a similar job a few years ago for a friend. It was a 200hp, but it is all the same for the V6s. It's a total strip down to get a cylinder bored, then a rebuild. It cost him $1,700 in parts, but that included 2 pistons and some carb work. My labour was on top of that.<br /><br />Chris................

 

[trumanlake]

Re: Black Max Piston Work

85 200hp bore and sleeve one cylinder new piston and rings for all gasket kit, rebuilt carbs, me doing labor. ran in the neighborhood 700-800. head gasket was the culprit.

 

[KCLOST]

Re: Black Max Piston Work

"each carb is in fact 2 seperate throats, feeding one cylinder for each throat. Which cylinder depending on whether the reeds are horizontal or vertical. So, he could have gotten the fuel supply for one throat clogged up and just killed the cylinder that it feeds."<br /><br />Like I said,,,"it could be a fuel+oil starvation problem"<br /><br />I suggest pulling the head and investigating the gasket and any damage, if there is any at all....<br />We need more information, like compression numbers and any other diagnosis that has been done... <br /><br />However, no matter what the problem is, you will have to pull the heads if there is a compression problem.. I'm hoping it is possibly something relatively minor...(gasket)

 

[KCLOST]

Re: Black Max Piston Work

The reeds are vertical by the way....

 

[KCLOST]

Re: Black Max Piston Work

GraAlaMat,<br /><br />Back to the cost....<br /><br />If you are sure of the culprit and damage...<br /><br />I'm going to go with a figure of $2000.... Hoping that you can find a repuatable dealer that will repair it... That is this biggest hurdle...<br /><br />Let us know...