191 Islander Issues

[jsmac51]

I have a 2005 Starcraft that I bought as a new leftover in 2006. I have really enjoyed fishing with this boat but have some issues with the performance as configured from the factory. The boat has the stock 4cyl with no performance enhancements. My problem is that the boat is VERY difficult to get on plane and top speed at WOT @ 4500 RPM even on flat calm water with only two people on board appears to be 25-28 MPH. I could probably live with this but I have had other 191's pass me even with more pepole on board the other boat. I have installed Bennet hyd trim tabs as advised by a marine mechanic and while this has improved some stability issues on plane it has not enhanced performance as far os top speed or hole shot. I am seriously considering changing from the stock prop and installing a whale tail to improve stern lift but what prop, larger/smaller and what pitch?

[blackcloud570]

I all so have the same boat. I love to fish out of it to. I have kind of the same problem. i can get her up fast w 2 people but top speed is 28. If you find away to speed it up, please let me know

[ray koziatek]

hmm could be a lot of stuff going on,rpm guage , tired engin,carb,exhaust blockage,if it was prop pitch (over) ya wouldnt get 4500 true rpms and she would come up slow sorta lugging .....

if ya got true 4500 rpm with the right prop it should come out good and strong..

The foam under the floor can absorb water as it gets old .when i redid my floor i removed a tiny bit near the back of the boat and the weight was unreal (waterloged).

If unapproved bilge cleaner was used along the way or water stood in the boat all season((winter) the foam could absorb water 19 ft x 6ft x6in(.5) could equal 60 cu ft of water dasa lotta weight even if 1/2 is soaked I guess to look at the waterline compared to a simular boat might give ya a clue or run it across some scales might give ya a clue..but remember in most descriptions of boat weight its without the powerplant,fuel,and equiptment.....

[MCF]

I had the old Sylvan Offshore 22 and ran that for 8 years, hull was a little shallower but I would guess it weighed in the same range as the 19 Islander. Also had the 3 liter.. On a good day it might have gotten 32 mph wide open so you are not that far off. Out of curiosity I would check that foam to see if it is in fact soaked which I would doubt on a 5 year old boat....Having had my first boat now with the fin, I would try that and you might pick up and extra mile or two on the top end. I believe you are close to the end in terms of top end range, that boat is not going to do 35 mph.

[muskybob]

I went from a 19 to 17 pitch prop and it made a world of difference on my 22' Islander. Comes out of the hole good & strong now.

[Tim Bromund]

If you are getting 4500 rpm at WOT, prop pitch is NOT your problem. My suggestion is to spend some significant time just driving the boat around and really learning your trim tabs. They take some playing with to really figure out, but they will make a world of difference in getting on plane quickly and running at your utmost efficiency. I have the electric Lenco tabs on my 24' Thompson and at the same throttle , I see a significant change in running speed and cruising rpms with just a slight adjustment in tab angle.

Tim

[Big Dave]

Put a dolefin on the outdrive helps with getting on plane and the bow bouncing when running . I have a 22' Islander with a 3.7 4cyd. I don't know what prop I have , buy I come up on plane at 16 to 17 mph and run at 25 mph at 3600rpm I don't run at wot and don't know what the top speed is. I am more interested in the trolling speed.

[Trap Jaw]

IMO, you may be able to get a bit more out of the boat, but with an I/O you're probably close to max.

Reason I say that. We just bought an old Chris Craft this spring. Almost the same boat as my buddy's, which we love. The only difference between the two is ours is an I/O and my buddy's is an outboard. He had his powerhead rebuilt last year and after that the 115 Merc. lost some power. Our boat has the 185hp 3.7 in it. His boat has a better hole shot and more top end, even after being rebuilt. Our boat came to us with trim tabs, but those do almost nothing for the hole shot. The I/O just doesn't have the RPM's to shoot out of the water. We went through the same thoughts you mentioned, and we had to deal with it and accept it, it's just the nature of the beast.

The other thing you should look at with regards to the other boats that "blow by" you is what kind of drive they have. Another buddy has the same boat you have, 19' Islander ~85-86 with a 115 Johnson, I know his boat shoots out of the water with 4 people and has a top speed around 35.

Just remember 2 things. One, that I/O puts a lot more weight in the back of your boat, and the more weight that's back there the harder it is to get on plane. Two, don't compare your I/O to an outboard. 2 strokes, by design, are better at producing power, why do you think anything that needed speed in a light package always had a 2 stroke, outboards, chainsaws, dirt bikes, snowmobiles. Keep in mind that while your WOT should be maxed out at 4500, a 2 stroke outboard should be 5000-5500. Heck, the last sled I owned had a WOT something like 7000-8000rpm, I just can't remember, other then it got squirely at about 100mph. I was usually too busy looking where I was going then to look at the tach.

[chowder]

I agree w/ Tim & Ray , if full gas and trimmed out you're really @ 4500 then you have the right size prop. I put a new style 4 blade prop on mine (I've got a 3.0 too) and put 250lbs of sandbags in the nose and she comes up better now. I think the 191 might come up on plane a bit harder than the 22' if it's got a lot of gear in it .No matter what you do to it though an Islander is not a ski boat and 28-30mph is probably fast enough for a light weight aluminum boat in a chop anyway(at least for me).

[here fishy fishy]

I HAVE A 221V WITH THE 3.0 AND LOADED WITH 4 PEOPLE RUNS 35 GPS AND COMES OUT OF THE HOLE STRONG..I THINK IM RUNNING A 21 PITCH..I HAD A 19 AND THE RPMS WERE TO HIGH...YOU HAVE TO PROP THE BOAT FOR WHAT U WANT THE BAD THING WITH THAT IS YOU CANT HAVE BOTH,EITHER TOP SPEED OR HOLE SHOT...TRIM TABS ARE GREAT IF USED CORRECTLY..ITS SOUNDS TO ME YOU MIGHT WANT TO DROP DOWN A COUPLE AND SEE IF THAT IS WHAT U WANT JUST KEEP IN MIND UR RPMS ARE GOING TO GO UP