50hp Force very sluggish

[Moto85]

Hey everyone! I'm just seeing if anyone out there has had a similar problem or is currently dealing with this that has some advice. I just acquired a 1989 Maxum 1600XR from my dad after he bought himself a new boat. He bought the Maxum last year from a dealership that told him everything checked out and worked great. It came with a 89 Force 50hp. Well, from the very first time putting it in the water the boat (with only one person at times) won't plane out at wot. Someone has to go to the front of the boat to get it to finally plane and even then it doesn't go over 15mph. The motor sounds great (working to hard for as slow as it is going) and looks very clean and taken care of. It doesn't stall or die at idle either. The current prop on the motor is an 11" diameter 11 1/2P. I know a different prop would most likely help out but I wouldn't think that much. I would post the serial and model # of the motor but they have both been rubbed off it would seem. Any advice anyone can give would be greatly appreciated because I am at a complete loss with having just spent $800 to get the motor fixed and literally no difference in performance at all.

 

[bowhuntrrl]

Re: 50hp Force very sluggish

50 HP Force =40 HP at the prop. They are not very powerful engines. I would only expect about 22-25 mph from your boat, best case scenario with no passengers and a small amount of gas on board. In other words, it's the "nature of the beast ". One other thought, have you checked the foam under the deck for being waterlogged ??? The other thing is that a 12 1/2 pitch would probably help some since that's what is normally found on a 50 Force.

 

[12Footer]

Re: 50hp Force very sluggish

I agree with bow on all points, and add one. See if the hub is slipping on the existing prop by painting a line from the shaft out to one of the blades and run it. If the paint line breaks, you need to rehub the prop, or get a new one. But before you get another prop, let me know.

 

[digger51]

Re: 50hp Force very sluggish

I am experiencing the same problem with my 89 50hp force, i get about 23mph out of mine. I think I will try that paint line on my prop, but is there a aftermarket prop you can get for these motors? I've looked everywhere I can think of on line with no luck at all.
Thanks

 

[12Footer]

Re: 50hp Force very sluggish

They only came in one pitch, so I think you'd have to have one made in order to get a different pitch. but Rich is right... The 50HP Force is equal to a 40-45HP today.
Chances are that everything is fine, but you have too much boat, and not enough motor. My Bayliner 1650 (16ft, 50HP Force)could only manage about 25MPH with just me and the dawg.

 

[Moto85]

Re: 50hp Force very sluggish

Thank you for the help all. I have checked for it being waterlogged and it seems alright there. Bought a new carb for it today and thinking about a 13 1/2 pitch prop but I don't know much about boats (this being my first one and all). And about the paint tip, does it matter what kind of paint at all? Thank you all again for the help, I'm going to run the boat tomarrow to see if the carb helped at all. I will post my results.

 

[12Footer]

Re: 50hp Force very sluggish

Any type of paint is fine, the more visable the better tho.
The line of paint will no longer line-up with itself if the hub is slipping, so any type of waterproof line will serve that purpose.

 

[bowhuntrrl]

Re: 50hp Force very sluggish

Thank you for the help all. I have checked for it being waterlogged and it seems alright there. Bought a new carb for it today and thinking about a 13 1/2 pitch prop but I don't know much about boats (this being my first one and all). And about the paint tip, does it matter what kind of paint at all? Thank you all again for the help, I'm going to run the boat tomarrow to see if the carb helped at all. I will post my results.

I wouldn't necessarily jump up 2 steps to a 13 1/2 pitch prop without a tach, unless someone is letting you try it first. You want the boat to tach out at 5200-5500 rpm @ WOT , if I remember correctly . Too much prop pitch is hard on your motor and it's possible the boat will be even more sluggish and slower.

 

[steelespike]

Re: 50hp Force very sluggish

paint to check prop needs to be indelable not water based.
Are the Force 50s really that guttless? I would think an empty boat would
at least manage 30 mph.My 50 Evinrude does about 20 on a 18ft pontoon.And I'm pretty sure it did close to 40 on the old 15 ft aluminum Starcraft.
Planed easily with 4 or 5 aboard.
You really can't tell where you are at without the rpm.If the motor is under powered more pitch isn't the answer.
Check the compression.Be sure it is running on both cylinders.Disconnect and carefully ground one plug wire at a time and see how it acts.
Be careful as you could damage the ignition if not properly grounded.

 

[Moto85]

Re: 50hp Force very sluggish

Thank you all for the help. This forum is great! I checked the prop with regular red spray paint and the line didn't break so I suppose thats a good thing. My cousin came with me and he checked the rpm and compression with some hand held gauges. I'm not familiar with them so I just had to take his word on it. He said the rpm was about 5600 @ wot and the compression was 125 and 126. The boat did run better. I got about 20mph (estimate) out of it today and it planed faster than it has before. And thank you bowhntrrl for letting me know not to get to excited and jump two up on the prop Most likely would run the same as it does now. I just had a few more questions and I'll stop bothering you all so you can go boating in peace. Are the instruments my cousin used accurate and is the compression supposed to be that high? And if I go with a 12 1/2 pitch does my boat have enough to pull a tube? Thank you all very much again, you don't know how much you've helped already.

 

[bowhuntrrl]

Re: 50hp Force very sluggish

That compression is fine. They normally run around 135-145 psi when new or in really good shape. Mine is about 135 on both cylinders. Mine gives about 22 mph on a 16' StarCraft aluminum boat with a 12 1/2 pitch prop. As far as the 12 1/2 pitch prop, it should only drop you down about 200-300 rpm, which still puts you in the range that you want to be in. You'll probably pick up some speed on top end, but the 11 1/2 pitch that you have now would be better for tubing.