slow to get on plane

[71whaler]

1983 75HP Evinrude. I had a problem with losing spark on #1 Cylinder. Mechannic replaced timer base wiring (burnt wire) and it ran great with just me onboard. The other day I had three people in the boat and it would bog at take off if both guest sat on the bench by the transom, it would be stuck at about 8 knots. If one of the guests would move forward, either next to or forward of the center console, the motor would catch up and run great, 30 knots. They could then move back to the bench and no problem. At idle it is firing on all cylinders. No rpm gauge. Any ideas? Compression good at 125psi on all 3.

 

[vranasaurus]

Re: slow to get on plane

What size prop do you have on it?

 

[CATransplant]

Re: slow to get on plane

What size boat, there? Could be you're just shy of having quite enough power, so the outboard can't get up enough speed to get into its power curve.<br /><br />Could also be that your setup or prop aren't quite as good as they could be.<br /><br />If you're really heavy in the stern, as you would be with two passengers sitting in the stern seats, but your boat planes out OK when you redistribute the weight, it's probably not your outboard.

 

[71whaler]

Re: slow to get on plane

It is a 17' Whaler Center console. I am not sure on the prop size. Should this be marked on the prop? I have had the boat for about a year and half and never had this problem before even with people in the stern seats.

 

[umblecumbuz]

Re: slow to get on plane

Just to get the layout - you're at the console, and there are two others on board, one in the port and the other in the starboard seat, alongside the outbord well - correct?<br /><br />I guess also that you've got a portable fuel tank somewhere in the stern?<br /><br />If you haven't got a foil or trim tabs, I'm surprised this problem hasn't arisen before.<br /><br />Possibly your motor is now tuned just a little different than before, which is why the problem shows itself. Whatever work you do on the motor, it will pay you to examine your setup. <br /><br />Check motor height (AV plate should be at or a little above the keel), check for any weight you can move forward (presumably the battery is under the console - if it's at the stern, can you move it?). I've mounted a spare fuel tank right up where my cooler used to be, and shifted my battery forward also.<br /><br />These steps will pay off regardless of motor tune or prop type and pitch.

 

[71whaler]

Re: slow to get on plane

Stillfishing,<br /><br />Thanks for the input. Actually the owner before me, built a bench that fits in the stern just forward of the motor. Under this are two 6.5 gallon portable fuel tanks and the battery. Here is a link to a picture:<br /><br /> http://pg.photos.yahoo.com/ph/pwbernhardt/detail?.dir=d6b0&.dnm=45a0.jpg&.src=ph <br /><br />On the day in question, both fuel tanks were full and both guests were sitting on the bench. I will try and move some weight forward and see if this helps.

 

[djzyla1980]

Re: slow to get on plane

It looks to me like the rear of the boat is much more heavier then the front. It doesn't look as if there is much in the front of the boat? <br /><br />Besides the wires what else has been done???<br /><br />A good thing about this site is it gives you alot of advice and help on problems... The bad part is it makes you realize all that is really wrong.. which in a way is a good thing all in it's own

 

[71whaler]

Re: slow to get on plane

Yeah, I guess I never really thought about it but the rear is pretty heavy. The only gear in the bow, is an anchor locker with 100' of line and a cooler with ice, beer and fish (hopefully less beer and more fish as the day goes on). <br /><br />As for work, on this past trip to the mechanic, he replaced the burnt wire, cleaned the #1 carb and replaced the head gasket as there was a leak in the #2 cylinder which caused it to occasionally misfire.<br /><br />Motor seems to run fine, starts right up on the first try and idles great. I will try redistributing the weight and see if that helps.

 

[CATransplant]

Re: slow to get on plane

I'm guessing that changing the weight distribution will really help. What's the maximum horsepower recommended for that boat?<br /><br />Any seats ahead of the console? If so, then I'd put a passenger or two up there as a regular habit. I'm betting your boat will perform better.

 

[CATransplant]

Re: slow to get on plane

OK, I see now, after looking at the photo. You really do have all your weight in the front. Since your seating is really spartan, how about putting a small jump seat of some kind in front of the console? That seems like it would be pretty easy to set up. You could even make it a folding sort of thing that drops a wide leg down when you unfold the seat. A hook could hold it up, with the leg automatically folding up or down as the seat moves. Throwable PFDs would be good for the seat and back, and the thing would be out of your way when you're not transporting a passenger.

 

[71whaler]

Re: slow to get on plane

I have a cooler which fits right in front of the console. I want to get a cushion which will snap right to the top of the cooler. The wife likes to sit there. The only problem is that the previous owner rewired the bow light to the front of the console so you can't lean back without leaning against the light (hurts the back). In old Whalers, pre1972, the bowlight wiring was directly in the hull, so once it goes you can't replace it. One solution is to run new wiring up the rubrail, which I will probably do and then get rid of the modified light on the console. <br /><br />I'll let you know how redistributing the weight works out. As for max HP, I believe it is 60-115HP for the 16'7 hull. I get 30 knots with 2 people and full gear with the 75HP. Anything above that and it would get very uncomfortable, Whalers aren't known for their gentle ride.