115 Merc 6 cyl inline, Stracraft Islander 191V

[Throbbin Rods]

Been chasing this problem all summer. Motor runs fair but is lacking in power. Changed plugs, all fuel lines on the boat. Rebuilt all the carbs. Tried it on a remote tank. Gas filter keeps getting crud in it but even with a brand neqw filter it doens't plane off too good. I have no clue where to turn next. Marina had boat for three weeks, gave up. Any ideas?<br />thanks<br />bill

 

[DJ]

Re: 115 Merc 6 cyl inline, Stracraft Islander 191V

TR,<br /><br />If your carbs keep getting junk in them, it may mean that your fuel lines, in the engine are coming apart.<br /><br />If your engine is older, the alcohol/MTBE in the fuel may be eroding the insides of your fuel lines on the engine side.<br /><br />BTW, that is one of my favorite boats.

 

[JasonJ]

Re: 115 Merc 6 cyl inline, Stracraft Islander 191V

Have you done a compression check? If it is lacking in compression, that would cause your problem. Also, do you have a tach? You need to make sure you are achieving max rpms at WOT. Check you prop, it may be pitched too high. Another thing, make sure the controls are adjusted right, I gained 500 rpms just by adjusting the cables (I was only getting 5000 instead of its max 5500). Lastly, check the weight of the boat. Is it overloaded with too much gear? Does it have waterlogged floataion foam? Is the motor trimmed right? There are a bunch of variables. Lastly (again), can you verify actual speed? Maybe your expectations and perceptions are different than what the boat will actually accomplish? I just got done rebuilding a Mercuiser 170 horse inboard in my friends little 16 foot ski boat, and after the breakin and top speed runs in that missile, my boat feels like it has three anchors tied to it. Anyway, good luck...

 

[Throbbin Rods]

Re: 115 Merc 6 cyl inline, Stracraft Islander 191V

Thanks to both of you.<br />I think it may be a bit over propped but it has run better than it does now. I had the same boat some years back with a 90HP V4 Johnson and it would eat this 115's lunch! The tacxh is running between 5000 and 5500 so that should be OK, just takes a heck of a long time to get there. One of my buds mentioned the possibility of plugged exhaust. Anyone have a good idea for that?<br />regards<br />bill finn