Speed Problems

[jlowe165]

This is my first boat. I bought a 1999 Bass Tracker Pro Team 175 Special Edition. It has a FORCE 40hp 2 stroke that was pushing the boat about 25mph. I shut the boat off and I was trolling then fired the boat back up and the speedometer was only going up to about 16mph. My question is what happend? The speed it gets up to seems the same as it was before but the speedo is not reading the same.

Also, motor sounds like it is missing when it gets up to speed and at full RPMs around 5000. Any idea what is causing it to miss?

The motor is smoking as well, I understand that it is supposed to smoke, but I don't know what is normal.

 

[Frank Acampora]

Re: Speed Problems

Running down the back of the transom is a small black plastic tube. It runs into the engine leg. This is the speedometer tube. On the lower unit above the gearcase and in the very front is a small hole. This is the speedometer impact tube. Something got in it and is partially clogging it. Clear it out and your speedometer should work correctly. IF by some chance you have a black or white plastic impact tube mounted on the transom, these flip up when you hit something. If you have one of these, simply push it back down to operating position.

 

[kmarine]

Re: Speed Problems

The hole in the speedometer airguide tube may have debris in it. Carry a paperclip on board to clear out the pilot tube.

 

[bentle]

Re: Speed Problems

The motor missing could be a fowled spark plug so check and replace spark plugs and get
An in line spark tester to verify spark on all cylinders.
May not hurt to do a compression test as well.

 

[Jlawsen]

Re: Speed Problems

Regarding the smoke, two strokes don't smoke except a little at startup and a very faint amount while running at speed. Any more than that and something is wrong with the engine. There is a long list of possibilities so rather than speculate, you should either take it in for service or try to fix it yourself by following the troubleshooting guide in the shop manual that you'll need to purchase.

 

[jerryjerry05]

Re: Speed Problems

Missing: could be water in the fuel,
or the fuel pump needs a rebuild.
Change the hoses,clean the carb.
Smoking:Too much oil in the system?

 

[jlowe165]

Re: Speed Problems

Thanks for the input. I checked the tube on the back of the transom and it wasn't clogged but looks like it was flipped up a little hopefully that fixed the speedo. The boat was out in the rain the other day so I guess it is possible it go some water in the fuel. I was thinking that I might have put to much oil in the mixture, what is the ratio for the Force 40?

The previous owner said that he had just changed the spark plugs but I guess I will check them out.

I was reading online and apparently you can switch to a smaller prop to run at higher RPM's and increase speed? The motor still has factory aluminum prop, what is the best fit prop for this motor to maximize performance?

 

[jerryjerry05]

Re: Speed Problems

50-1 oil/fuel.
Trying to figure out the proper pitch???
What size prop/pitch on it now?
You will need an acurate tachometer.
Install tach and go for a ride.
The motor should reach 5200-5500 wot.
Higher than 5500? Say your prop is a 12x13p
Then you can go up in pitch to a 12x15
Lowe than you need to drop to a 12x11 or 12p
Most times the boat motor combo is set up right,unless the motor was installed as a replacement???

If you try to run a bigger prop to get more speed your economy is gonna suffer.
I replaced my 17p with 19p to get a bit more speed.
I got about 3-4 mph but my fuel consumption went up about 20%