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1998 pro Vmax losing top end power?

skeeterdan

New member
Hi. i bought a 1998 pro vmax trp and it seems to lose power at high rpm. i could barley get it over 30mph yesterday while a few weeks ago i had it a 60+. I checked a bunch of stuff, changed plugs, rebuilt carbs, adjusted throttle ,new filters and still nothing, gas lines all look fine. one thing i noticed is when i fired it up in the garage is after i let it run for abit the left side cylinder block was fairly cold compared to the right side, i checked the spark to make sure it wasnt a faulty cdi and they seemed fine. i dont know what else to do?
thanks
 
NO I don't have an IR gun, there was just a big temp difference when I felt it With my hand, I took the boat out on the lake for a run tonite and it ran great for 5mins then started losing power again, I'm thinking it's the fuel pumps because the power is of an on. Also after I ran it on the lake I felt the blocks and they were both warm which is a good sign
 
Chances are you have some debris inside the fuel nipple on the carbs before the float seat. Remove the carbs again, remove the float bowls and the floats, blow back from the needle seat side and see what comes out.
 
I have the same motor that had the same problems. I replaced everything and still nothing. But I found the problem, disconnect the main wire harness connection and look for corrosion. I found 3 pins badly corroded that were intermittently shorting out at high rpm. I bypassed the 3 pins and it runs great.
 
Its located just to the right of your throttle linkage. Its a large quick disconnect with about 8 - 10 wires. I have taken my Skeeter out about 6 times since I found this problem, and its running great. Look at my past threads and you will see what I went through and how it was not running, before I found this. Hope this helps. and sorry for the delay.
 
Perfect timing for this top end power problem. I just returned from Rockport TX and had the same issue. I purchased new fuel pumps and replace the main fuel line from the tank to hand pump. This fixed motor starving for fuel found a crack in line of all things. Now the motor fuel stayed primed but had to keep pushing down the choke switch (at Key switch) to get motor the rev up. I maybe it just sit to long during the winter months and the fuel with corn alcohol maybe a problem as well. Added 20 gallons new fuel and motor started getting better as we ran it each day.
One new problem we had was the main oil tank was not pumping as well. Today I removed the cover and see the switch to over ride the large oil tank to fill top tank and see it is not working as well. I'm new to the Yamaha threads and if anyone can help I would really appreciate. Mine is a late 1997 been a great motor on my 22' never has really been and fast moving boat but goes shallow used to run near 40 now at 20 with the rpm running at 4K.
PS checked the 13 pin and 3 pin connectors and not a bit of corrosion here....
 
Perfect timing for this top end power problem. I just returned from Rockport TX and had the same issue. I purchased new fuel pumps and replace the main fuel line from the tank to hand pump. This fixed motor starving for fuel found a crack in line of all things. Now the motor fuel stayed primed but had to keep pushing down the choke switch (at Key switch) to get motor the rev up. I maybe it just sit to long during the winter months and the fuel with corn alcohol maybe a problem as well. Added 20 gallons new fuel and motor started getting better as we ran it each day.
One new problem we had was the main oil tank was not pumping as well. Today I removed the cover and see the switch to over ride the large oil tank to fill top tank and see it is not working as well. I'm new to the Yamaha threads and if anyone can help I would really appreciate. Mine is a late 1997 been a great motor on my 22' never has really been and fast moving boat but goes shallow used to run near 40 now at 20 with the rpm running at 4K.
PS checked the 13 pin and 3 pin connectors and not a bit of corrosion here....


Took some time looking at the oil sending unit today, (with Key ON) the over ride switch does work it will fill the motor tank with oil. But looks like the auto fill option is not working. should I check out or replate the small tanks sending unit? the float may be not working? but it does tell you when low for the horn / busser come on.
 
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