yamaha F225 stalling

[subfixer]

I am fighting what seems to be fuel starvation problem on my F225, 4 stroke. Problem started after installation of a Sierra fuel/water seperator. After a long shutdown it is hard to prime. After starting it runs ok until I throttle up and then it will stall. If I then re-prime it will start and run fine at all speeds. I have checked all fittings, replaced all in line filters, repositioned and shotened all lines to and from the seperator, replaced the check valve at the tank, new primer bulb, etc. Next I will install a fuel selector valve at the water seperator so that I can pull fuel either directly from the tank or through the water seperator. Does anyone know if the Sierra 10 micron filter bracket has an integral check valve? If not, I think I can pull fuel straight through the two ports that show a flow in arrow. Thanks for any help or suggestions.

 

[jeffersondodson561]

Re: yamaha F225 stalling

Next time this happens, drain the VST and put into graduated cylinder, record reading. Next prime the bulb until slight pressure is felt, drain VST again into same mesuring device and record. If you have a significant difference you definately have a fuel restriction. The only person that has told me that Sierra parts are good, is the salesman selling them.

 

[subfixer]

Re: yamaha F225 stalling

thx for the suggestion. This doesn't happen when running on the trailer with the shift disengaged. I don't think I'll be able to get to the VST drain while on the water. I just replaced the F shaped filter on the VST side of the low pressure fuel pump. (latest Easter egg)

 

[jeffersondodson561]

Re: yamaha F225 stalling

Dignosing on the trailor is harder than in the water, I would try and replace every filter you can rather than just one that you suspect. What did you use to secure the hoses with? I perfer Oeticker clamps, have to remember that when you added the water seperator you added a slight restriction to the fuel system. I have always after installing any component to the fuel system whether it be valves or water seperators tested the whole fuel system with a low pressure (4-6psi) fuel pump hooked up with a vacuum gauge, I would hook it after the on engine filter and record reading anything over 4"hg definate fuel restriction. Here is the thing with boats, boats have to pull fuel to them. Vehicles push fuel to the engine. That is why fuel restriction is so critical to outboards. If you have seen Bill Nye boil water just by pulling low pressure (vacuum) on water...just imagine how easy it would be to do that to a volitale substance like gasoline, to the point of vapor lock sometimes.

 

[99yam40]

Re: yamaha F225 stalling

Always test things, then replace what you think is the problem, and retest. it is the only way to be sure you have fixed the problem.
Or you can throw parts at the motor until you think it is fixed or it is damaged way worse than you would like to repair.

Taking fuel pressures at different points in the system will pin point a restriction if there is one.

Have you thought about the new filter plugging or sucking air?

 

[subfixer]

Re: yamaha F225 stalling

thx again. I have replaced all of the filters and primer bulbs and looked for air leaks or poorly seated components. Hopefully when I bypass the water seperator, I'll know if that has introduced a significant flow restriction. I'll get set up to measure fuel pressures and vacuum, as you suggested. Do you simply disconnect at the engine filter and install the pump and vacuum guage in the line, while pumping into an external container? Does anyone know if there is an internal check valve in a Sierra water seperator bracket?.......many thx

 

[99yam40]

Re: yamaha F225 stalling

I would not flow the fuel in the opposite direction than the filter is meant to flow.
Check while motor is idling/running to start with and then while having the problem.


there are more filters in the system and checking fuel pressures along the way and even the rail pressure at the same time will help diagnose problems.

A clear piece of tubing temporarily installed on suction side of lift pump may show air bubbles if sucking air

 

[subfixer]

Re: yamaha F225 stalling

A bit more info, JIC anyone else is wondering about the Sierra filter bracket, as I was. A Telefex rep. told me that the Sierra filter bracket does not have an integral check valve. They do not recommend that both of the inlet ports are used however, just as yam stated. They recognize that many filters have an internal anti-siphon valve that would not allow flowing from inlet to inlet. I don't see how that would happen if the gas wasn't going throgh the filter but I am certainly not going to take that chance. This may have a bearing on folks that have two tanks and are thinking of using just one filter. If you do try that you had better put shutoffs on both inlets and check for proper fuel flow from each side.

 

[subfixer]

Re: yamaha F225 stalling

I tested the fuel tank vent hose to make sure it was clear. It is, but the Perko vent and fill cap has me puzzled. The vent hose exit is in the neck of the fill connection, but it doesn't seem to have an escape path when the fill cap is installed. The cap has a drilled path through it but there is button on the tank side (labeled purge) that seems to close with tank side pressure. Also the drilled vent passage looks to be sealed when the gasketed fill cap is tightened down. My fill connection is mounted vertically, high on the gunwhale. This connection may work better if it was a horizontal installation, so that the "purge" button was held open by gravity. Has anyone seen tank venting problems with these Perko combo fill/vents.

 

[subfixer]

Re: yamaha F225 stalling

After installing a bypass valve around my boat's water seperator filter, I measured fuel rail pressure and fuel line vacuum at the suction side of the low pressure (ie. lift) fuel pump. All readings were in spec. at both idle (about 950 rpm) and at 1500 rpm. Fuel line vacuum was 2.5" and rail pressure was 40#. Selecting the water seperator in or out and installing or removing the fuel filler cap had no measurable effect on vacuum or pressure. I permanently installed the test fittings so that I can measure these values again, if I have the problem return when waterborne.
While working on this, I noticed another fuel filter and a canister tucked way in back of the engine cowling. The only place this shows up in my Yamaha service manual is on a schematic of the cylinder head. The Yamaha parts/service website shows it on an intake schematic. Neither place shows the purpose or connections. The canister has three hoses. One hose connects to the port side intake manifold ( for vacuum I assume). A second hose tee's into connections (2) on the top of the VST and into the intake silencer. The third hose goes to a F shaped fuel filter and then terminates at a connection on the port side cowling latch. There is no other fitting or connection on that latch, so I assume that there is an internal passage in the upper unit that goes somewhere. I am guessing that it goes to the engine exhaust and provides a vent path for the VST. But if that is the case, why the filter? Info about this filter and cannister would be appreciated. By the way, the Yamaha service manual ($ 125.00) leaves a lot to be desired.
If this problem persists I'll be into the VST and injector cleaning.

 

[jeffersondodson561]

Re: yamaha F225 stalling

The third hose goes to a F shaped fuel filter and then terminates at a connection on the port side cowling latch. There is no other fitting or connection on that latch,

The hose that goes to the latch is the VST overfill, should the needle and seat in the VST not close up and stop incoming fuel, their will be an overboard discharge of fuel out the latch fitting...

 

[subfixer]

Re: yamaha F225 stalling

thx (again) jeff....I am trying to understand the operational theory of this whole assembly. Is this thing a VST vapor vent as well? Is the tube that goes to the intake providing the suction for any fuel vapor? One of the tubes goes to two fittings on the top of the VST. The hose that goes to the latch comes from the other end of the canister and has a filter in line before it gets to the latch. Does the VST overfill pass through the canister and escape out the line to the latch? And why is there a filter in that "escape" line? How does fuel get out of the latch? ..........SOooooo many questions!

 

[jeffersondodson561]

Re: yamaha F225 stalling

You know I would have to study the fuel flow of the manual, Yamaha manuals are straight and to the point. Their is no theory of operation like BRP and Mercury, but their tech guides are gold. That F shape filter may just be a sight tube or a return filter to the VST. I have never found that filter to be a problem but have replaced just by principle.

 

[subfixer]

Re: yamaha F225 stalling

thx........If this thing works similar to other vapor removal charcoal filters, I am guessing that the filtered line removes excess fuel from the charcoal media so that the air/gas mixture at the intakes isn't thrown way off. If that is the case, the fuel connection on the cowling latch has got to get back to the VST somehow. In any event, that probably has little to do with my problem.

 

[subfixer]

Re: yamaha F225 stalling

One more thing...........How do I get the yamaha tech guides? I don't see them on the Yamaha motors web site.

 

[jeffersondodson561]

Re: yamaha F225 stalling

You could search on Ebay or something like that, they are more for mechanics to assist with service bulletins and warranty claims. I am not sure how you could get your hands on one?

 

[99yam40]

Re: yamaha F225 stalling

One more thing...........How do I get the yamaha tech guides? I don't see them on the Yamaha motors web site.

You might try asking your local Yamaha dealer politely to see if they will share them with you is my only thought

 

[seahorse5]

Re: yamaha F225 stalling

One more thing...........How do I get the yamaha tech guides? I don't see them on the Yamaha motors web site.

Your dealer can order them for you. Which one(s) are you looking for? You are talking about the annual Marine Technical Guides that each dealer gets, right?

 

[subfixer]

Re: yamaha F225 stalling

thx....Yes I am. I am basically intersted in any motor related topic. Currently I would like to have any fuel and intake related information. I am nearing 500 hrs on my F225 and will be doing some more in depth maintenace ( timing belt and chain, injectors, poppets, throttle body synch's, etc.). I'll check with my local dealer..........much appreciated.

 

[mt799ph]

Re: yamaha F225 stalling

I am fighting what seems to be fuel starvation problem on my F225, 4 stroke. Problem started after installation of a Sierra fuel/water seperator. After a long shutdown it is hard to prime. After starting it runs ok until I throttle up and then it will stall. If I then re-prime it will start and run fine at all speeds. I have checked all fittings, replaced all in line filters, repositioned and shotened all lines to and from the seperator, replaced the check valve at the tank, new primer bulb, etc. Next I will install a fuel selector valve at the water seperator so that I can pull fuel either directly from the tank or through the water seperator. Does anyone know if the Sierra 10 micron filter bracket has an integral check valve? If not, I think I can pull fuel straight through the two ports that show a flow in arrow. Thanks for any help or suggestions.

after reading your initial complaint and briefing thru the threads, I just had to respond. I too had the very similar symtoms w/ my f225. After replacing just about everything over the course of a couple years, and discussing the issue many times with my service mgr to no avail. I decided to try running high test and guess what? haven't had a problem since. I am convinced that the culprit is likely an ethanol issue. If you have not yet resolved, it's worth a try, hope this helps. I been there, done that and it's very frustrating and can be a real serious safety concern depending on the situation.