1989 Bluefin w/50HP Force speed?

[funnyman1969]

I recently purchased this boat and was curious if someone could tell me what the top speed should be roughly? I can only get 18mph at full speed with two adults in it. Ironically, the same speed with 4 adults in it. Any suggestions? I replaced the plugs and it seems to be running very smoothly, but also seems like it can give more than it is. Thanks for all replies, this is a great forum!

 

[roscoe]

Re: 1989 Bluefin w/50HP Force speed?

Welcome to iboats.

Could use a little more info.

But assuming the boat is approx 16-16.5 ft long, and the 2 adults weigh under 400# total, I would think you could get 25-30 mph out of it.

18 mph -- taken with the boat's speedo, or a gps?

The speed should go down with 4 adults in it.

How long does it take to get on plane?
It will run very smoothly on only one cylinder.
Check for spark on both cylinders.
Check compression.

Check that the throttle is opening up all the way in the carb throat (horizontal.)

Does your boat have a tach?
If so, what are your rpm's at full throttle?

Do you know the diameter and pitch of the prop?

 

[funnyman1969]

Re: 1989 Bluefin w/50HP Force speed?

Thanks for replying. The speed was taken with the fishfinder, not GPS. I will take my GPS next time. It does not have a tach. Based on the part number of the prop, I think it's a 12.5 pitch with a 10 1/8" diameter. I will check for spark on both cylinders. It appears that the butterfly is opening all the way, horizontal.
I don't have the equipment to do a compression test. I'll let you know how it turns out. Can you tell me if it has something to do with the prop pitch? It seems to get to plane pretty quickly. It has those trim helpers on the motor, sorry for the non technical term. Thanks again.

 

[roscoe]

Re: 1989 Bluefin w/50HP Force speed?

If you had the wrong pitch prop ( like a 19 pitch) the motor would not get on plane very fast, and the motor would be struggling to get into the upper rpm's.

 

[Frank Acampora]

Re: 1989 Bluefin w/50HP Force speed?

Go to the menu and check the speed setting on your fish finder. They range from plus 1.25 to minus 1.25. so, you could be reading 25% less than actual. Or, you may be reading Knots instead of MPH

 

[funnyman1969]

Re: 1989 Bluefin w/50HP Force speed?

In reading other replies in the forum, I read about the vent cap not being open. I checked my tank and sure enough it was tightened down and the tank sides were collapsed a bit. Could this be part of the problem? Thanks for all the replies again, I appreciate it. As I learn, hopefully I'll be able to help others too.

 

[roscoe]

Re: 1989 Bluefin w/50HP Force speed?

Could this be part of the problem? yes

Good find.

 

[steelespike]

Re: 1989 Bluefin w/50HP Force speed?

The Force is not known for its performance and I think the prop size if correct
for the application is undersized compared to a typical application.
The modern day Etec 50 on a heavy hard to push 23 ft pontoon runs a prop
in the 13 X 13 range and makes 19 mph at about 5,400 rpm.
All trhat being said I agree that your setup should run in the 25 to 30 mph range.By the wayWhat size boat are you running?

 

[funnyman1969]

Re: 1989 Bluefin w/50HP Force speed?

It's a 16.5 foot boat.

 

[LTLhawk]

Re: 1989 Bluefin w/50HP Force speed?

I have an 1989 Bluefin bass boat with a force 50HP on it. It goes 28mph with just me and about 24mph with two people. I tested the speed using my gps. I do not have power trim and hope to get for next season. THat will help me get to plane better.

 

[Shife]

Re: 1989 Bluefin w/50HP Force speed?

I have a 1987 Bluefin S170 fitted with a '87 "B" series Force 50. I can get about 27mph out of it right now with a 11.5 prop. I just purchased the boat in August and while it had very little use, it also had very little maintenance. The points and condensers need to be replaced, along lots of other little things. If the winter teardown reveals any major issues, I'll toss it in favor of something bigger and easier to source parts for.

When I pull the boat out of the water this weekend and start tearing the deck out and pulling apart the outboard, I'll probably start a thread in the restoration forum.

Also: Get a manual for the outboard (you'll need it) and be sure to decarb it. Mine would hardly run when I bought it. After a can of Deep Creep it ran much much better. After adjusting the points it ran great (slight intermittent miss due to a worn point still).

 

[puddle jumper]

Re: 1989 Bluefin w/50HP Force speed?

We get about 20 mph with 3 people and fishing gear. I have a 89 1700 17 foot.

As of for the prop I think you can only get the factory pitch for that motor.