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08 Puma Yamaha VZ 250 25 T1 Will start with thought it was just me and driving abitlity but after 20 hrs and several hundred miles in all kinds of water here we go. Started out at 5600 RPMS @ 71.8 cooler water now down to 5400 RPMS 68.5. I dont think the hot foot is adjusted to give me WOT. Read alot of posts on checking throttle valves for WOT and the manual on syncronizing throttle valves and adjusting throttle cable plus TPS output, if it is just the hot foot I shouldnt have to adjust the output should I. The boat is in storage at the lake 215 miles away. Want to see if when I get there I can check and adjust it without much problem. Last time tried adjusting the foot stop a little with no difference. Doesnt effect the fishing ability just to many boats passing me. Hope it isnt just the Hammer dragging me down. Think I ought to be able to see at least 5800 to 6000 RPMS. Prop slip is approx 8% which is OK right. 1000 Elevation ThanxLast edited by tschooler1956 on April 22nd, 2009, 12:12 am, edited 1 time in total.
It could be not opening, and it could be engine height and more. That is not high at 1000 and the boat should run into the mid 70s if setup well.
and more what have adjusted the JP from 3.25″ to 2.5″ below pad, loaded the boat every way to think of and run the fuel in the saddle tanks and belly tanks all kinds of ways, trim up , trim down. The steering torgue is minimal and rooster tail looks great, even or lower than cowling. Every things seems great but the RPMS. Been tweaking on the setup and just now started looking at WOT. Would like to get it right from my knowledge so i know how to do it again. Thanks Great site BCBLast edited by tschooler1956 on April 22nd, 2009, 12:28 am, edited 1 time in total.
I cant imagine you needing to adjust the TPS. If the hotfoot came from the factory, Id also bet on it being installed correctly and adjusted. But just have someone stand on the throttle while you go look at the throttle linkage. You can see how the stop works on the side of the motor. Does the throttle hit the stop? If not, adjust the hotfoot stop by screwing it in to lett the pedal go further down. You just dont want to exert a ton of pressure on the throttle linkage by going too far in the hotfoot adjustment. You should be able to remove the silencer and see the throttle butterfly. When you stand on the throttle, does it turn edge-wise so that you just see the edge, or is it occluding the throttle bore somewhat by not quite going far enough (or too far, I have seen some that would go past the level point which is also no good and can confuse the ECU as well with an odd TPS reading.) You want the linkage on the power head to hit the stop as the butterfly fully opens, then you want to just lightly hit that stop when you press the hotfoot pedal all the way against the pedal stop. Thats as good as you can set it. If you want a more careful test, put a piece of paper between the throttle linkage and stop. Stand on the hotfoot and pull the paper out. It should come out without tearing or requiring a lot of effort. If it doesnt, back the foot pedal stop out a half turn, lock it down, and try again…2008 Pantera Classic2014 Mercury Pro XS 200
Thanks Old Timer, When I get to the boat this weekend the butterflys edge on at WOT against the stop lightly will be the first thing I check. Just cant understand, I adjusted the pedal stop screw in some didnt make any difference. Surely 5400 RPMs @ 65 degree water / 90 degree air with 25P T1 and some good advice on setup is all this 250 Hammer will do.
After that, there are other things to check. You could have a prop that is incorrectly pitched. Add a couple of extra inches of pitch and the RPMs will fall off. Or you could have a simple or complex motor issue. Might need plugs. Might be starving for fuel a bit due to a dirty filter. Etc. That motor should certainly run past 5400 if all is well. Give it a chance and it will run past 6000. 2008 Pantera Classic2014 Mercury Pro XS 200
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