Yamaha 150 2001 won't start.

My 2001 Yamaha 150 Z150TXRZ won't start. The engine ran fine last year and now after winter storage won't start. I drained the low pressure reservoir for storage last year. The engine will fire as if starting and run for a few seconds with gas sprayed into the intake. The low pressure pump is pumping as when I disconect the hose to the High pressure pump a stream comes out, also a stream when I depress the tire valve test port, although not with any great pressure. I tried hooking the tank gas line directly to the High Pressure intake and by squesszing the bulb tried to start it but same thing. Do I have a HP pump problem? Any other trouble shooting ideas?

Re: Yamaha 150 2001 won't start.

Yes you have a high-pressure pump problem. I?ve had luck with this over the years so here it goes. Before you go spend 800.00 bucks on a new one try this. Remove the canister and all the screws taking care not to stretch the oring. Remove the high p.s.i pump and take off the filter and filter plate. When you have the pump on the bench go and bay a pale of carb cleaner at the auto parts store. Put the pump in the fluid submerged for 15 minuets or so. After that remove the pump and drain. Get a set of jumper wires and connect them to the pump. Connect the hot lead to a battery and tap the negative lead on the ground post on the battery. If the pump spins your good to go. Just rinse the pump out with water and fill with light oil to lube it. Dump oil retry to be sure its still working and reinstall.

Re: Yamaha 150 2001 won't start.

pay no attention to the carb cleaning post, better method with less risk of damage.
use seafoam or Yamahas compustion chamber cleaner, no chance of damaging the internal seals or plastic parts.
soak the pump overnight then hit it on the jumper, dont be scared to reverse the polarity sometimes you have to shake it back and forth. DO NOT rinse with water.
just so we all get on the same game card, low pressure is the 2 lift pumps, medium pressure is the pump in the VST, high pressure is the belt driven pump that steps it up to about 700 PSI.
occasionally I have to whack the pump with 24Volts to break it free, on rare occasions I get to whack a customer with an 800 dollar pump.
but its hard to look a customer in the eyes and charge 800 for such a silly pump.
so over the years I have experimented with both storage and how to break them loose methods.
I dont have many issues with them now but I dont follow any published guidelines anymore.
just keep in mind, low pressure,6 psi at wot, medium pressure 50 PSI and high pressure, roughly 700 psi when disscussing pumps on HPDI

Re: Yamaha 150 2001 won't start.

Thanks for your quick response. I'm sure you both are right but I'll certainly take your advice on trying to rejuvenate the costly pump. How should the pump be treated for winter storage? The pump seems to work slightly at times, yesterday while troubleshooting it would run and pump but didn't seem to have a strong flow. I made up an attachment for a presure gauage and now the pump doesn't run at all. I have 12 v at the terminals.
Bob

Re: Yamaha 150 2001 won't start.

Regarding the above problem. When I went to drain the tank in preparation for disassembly, I found it almost dry. This is after much cranking and priming. I disconnected the input hose and cannot prime fuel through. It goes through the filter but not the 2 low pressure pumps. Am I chasing a different problem?

Re: Yamaha 150 2001 won't start.

That?s right pay no attention to me. Im sure you could tell that I don?t know what im talking about. Just to clarify before the H.P.D. I. Models came out the vapor canister pump was referred to as the high-pressure pump. Sorry if I stepped on any ego?s.

Re: Yamaha 150 2001 won't start.

Boy's...Boy's....play nice now

Good thread. Info I needed. I'm doing VST myself for the first time this weekend. Not to hijack, but if the o-ring on the VST comes in contact with fuel and gets out of shape, does the cat litter in a baggie thing to dry it out really work?

Re: Yamaha 150 2001 won't start.

we have a mobile tech here that tried the carb cleaner soak, thats how I found it can destroy a pump.
if an oring is swelled or distorted its time for replacement.
I have unstuck many a pump with combustion chamber cleaner and a hit with 24V, occasionally you have to play with polarity reversing a few times.
that pump is about 700 dollars so I try to save them.
if you use 24V(lst resort) then only bump it dont run it and never run it dry.
combustion chamber cleaner is actually a decent lubricant as well as a solvent.
no ego's got stepped on.
I try to prevent folks from doing something I have seen create more issues.
and yes the VST pump on an OX66 and certain other EFI yamahas is called the high pressure pump, just not on the HPDI models.
on the fuel inlet issues, remove the drain plug from the VST and try pumping it again, if no fuel flows you may have a stuck float needle at the VST inlet.
the medium pressure pump has 12V+ at the red lead anytime the key is on, ground path is completed by the ECU for the 5 second prime run at key on and anytime the ECU has an engine crank or an engine running signal.
if the engine quits rotating for any reason the ECU removes the ground and shuts off the pump.

Re: Yamaha 150 2001 won't start.

I want to thank you all for your assistance. However the problem turned out easier then I thought. The check valve between the filter and the low pressure diaphragm pumps was frozen and wouldn't pass fuel. I bypassed it temporarily and it runs fine now. I know trying to trouble shoot by email is a tough one but I learned a lot from you regarding fuel problems on my Yamaha. I wonder if that check valve is important? They don't show it in the manual I looked at.

Re: Yamaha 150 2001 won't start.

Your welcome Bob. The rest is all yours Rodbolt.

Re: Yamaha 150 2001 won't start.

parrfive, dont get bent, just be aware I have done this 6 months and stayed at a holiday inn once.
if your a yamaha tech please feel free to PM me as I actually do have 6 months experience with outboards,sterndrives and inboards, and I stayed at a holiday Inn once.

as far as the check valve. eliminate it, run a solid line from the engine filter to the pump inlet. was a bad Idea from the start.