98 vmax 150TRP fuel problem

[19maverick88]

hello and thanks ahead for reading and or replying. I have a Yamaha VMAX d150tlrw and am having problems with bad idle and stalling. It started after trolling for awhile one day, I came to neutral and the motor choked out. I tried restarting and constantly choked to a stall. I was able to rev the motor a little and put it into gear and keep it running barely without it stalling. As soon as i came to neutral it would stall again. The primer ball was firm and pumping while running did nothing. I could keep it running by using the choke switch intermittently (every 5-8 seconds). I check the carb drain screws and took each one out and pumped the ball and fuel pumps through, so I dont think its the float/needles getting stuck. I also tried the fuel pumps by releasing bolts and checking for fuel leakage from the back which would be a whole in diaphragm. It will run in idle only if I choke it before it stalls. Maybe the fuel pumps?

 

[19maverick88]

Re: 98 vmax 150TRP fuel problem

I tried the new fuel pumps and that was not the problem. Now it seams like plug #6 and #3 are not working ,but there is spark. I am taking it in for carb work/cleaning, unless rodbolt has any ideas!

 

[Poorman]

Re: 98 vmax 150TRP fuel problem

I would replace the plugs. I have seen a many of plugs fire while grounded on the engine but create problems under compression. Most likely they got loaded up with fuel during the long idle.

 

[rodbolt]

Re: 98 vmax 150TRP fuel problem

my idea is the same as yours,clean the carbs.
fuel pumps should be changed every 3 years or so cause they do wear out and fail but your not describing a fuel pump issue your describing a clogged idle fuel jet.
AKA pilot fuel jet.
easy to clean after removing the carbs.
by hitting the choke you force the system rich by bypassing the main and idle fuel jets and dumping fuel into the reed box.
thats why I say your describing a clogged jet.

 

[19maverick88]

Re: 98 vmax 150TRP fuel problem

Thanks for writing back with your ideas. New plugs were first. I will have the carbs cleaned and back from the shop in about ten days. After the test run I will post, with problem solved hopefully.