Vapor lock solution in F225 03

[keyscrazy]

OK, don't laugh but - battled vapor lock after running down numerous other rabbit holes. Dealer wanter to install tech bulletin which included rerouting fuel lines and a charcoal filter etc. They say I missed the recall they did on the 02, 03, and 04 before they did a redesign on the motor. It would cost about $1500 and one of the mechanics mentioned it doesn't always solve the problem all the time. I decided its the buildup of high temps under the engine cowling and when fuels sits it vaporizes. My theory is winter blend fuel is the worst, but thats neither here nor there.

Solution - I installed a blower on a hose attached to the front of the cowling. This keeps a constant airflow through the cowling when stopped or at idle speed. I tend to just run it all the time. I have used it for a year now and it works great. When I try to not run it I end up back at lock - like when the Coast Guard pulled me over and I shut down the engine and blower. Downside is NOISE and small current draw. Upside is $75 and its fixed. I worried about cutting the hole and affecting resale but they were only going to give me a few thousand on trade in value. Maybe I should patent the design - someone told me the new Mercury 300 has a blower inside.

[99yam40]

sounds like an over rich condition under the hood at hot restart, not vapor lock

[TownsendsFJR1300]

OK, don't laugh but - battled vapor lock after running down numerous other rabbit holes. Dealer wanter to install tech bulletin which included rerouting fuel lines and a charcoal filter etc. They say I missed the recall they did on the 02, 03, and 04 before they did a redesign on the motor. It would cost about $1500 and one of the mechanics mentioned it doesn't always solve the problem all the time. I decided its the buildup of high temps under the engine cowling and when fuels sits it vaporizes. My theory is winter blend fuel is the worst, but thats neither here nor there.

Solution - I installed a blower on a hose attached to the front of the cowling. This keeps a constant airflow through the cowling when stopped or at idle speed. I tend to just run it all the time. I have used it for a year now and it works great. When I try to not run it I end up back at lock - like when the Coast Guard pulled me over and I shut down the engine and blower. Downside is NOISE and small current draw. Upside is $75 and its fixed. I worried about cutting the hole and affecting resale but they were only going to give me a few thousand on trade in value. Maybe I should patent the design - someone told me the new Mercury 300 has a blower inside.

Can you post a pic or two?

Did you try calling Yamaha direct and see about a "goodwill fix"? Heck, you may not have even owned the motor back then..

[fairdeal]

sounds like an over rich condition under the hood at hot restart, not vapor lock

Or as Yamaha themselves have explained it:

"Just after the engine is stopped, the cooling-water supply is also stopped and the heat is conducted to the VST from the engine, causing birth of many fuel vapor gases.

…So the canister has been used as a damper for returning the vapor gases into the intake silencer, which can obtain to easy restart the engine while it is warm."

[rodbolt17]

I love to watch "birthing gasses".

I alsso love to watch " obtaining gasses".

ya folks that is out of a POORLY translated Japanese to English manual.

kinda like the alarm system when the engine has a "fever".

had you inspected/replaced the check valve between the VST vent and the airbox that issue would have probably disappeared long time ago.

vapor lock on an EFI is almost impossible,it can be done but not on a cold or semi cold restart.
only way it happens is when the fuel cooler fails and the fuel inside the VST gets hot enough to boil.
yes I have seen it,usually on Volvo motors where the VST clogged with sand.
typically it takes out the HP pump.

on some of the early 4 strokes the VST vented via a relief valve that supposedly stayed sealed until about 7 PSI.
after that it would vent vapors into the airbox.
if the valve failed and they did it vented ALL the time.
made the hot restart VERY rich.
remember its EFI.
means the ISC valve has already reset to allow air for the next start cycle.
at key on the ECU locks in baro pressure(air density).
when you hit the key fuel and ign timing are fixed until it starts and the ECU can start "looking" at the various sensor inputs.
means with vapor ALREADY in the air box the fuel mix is to rich to start.

this can be easily found by simply cracking the throttle a bit BEFORE starting.
if it now hot restarts easily you know it is getting vapor in the airbox.
cause you added enough air to make the mix lean enough to burn.

this is why MOST EFI motors,hot or cold, start at a target RPM of 1000-1100 RPM.

[boscoe99]

Can you post a pic or two?

Did you try calling Yamaha direct and see about a "goodwill fix"? Heck, you may not have even owned the motor back then..

Yamaha US' thought is that if the motor did not need the vapor recovery kit in the first ten years of its life that if there is a problem after the 10th year it more than likely is not related to the failure to restart in a hot condition.

Also, there has to be some time limit to helping folks out. Otherwise the corporation would go broke. Trying to be all things to all customers. And all Yam owners would then suffer.

Kudos to the OP for coming up with his own innovative solution. I think others have simply routed the VST vent over board so that excess fuel fumes are not dumped into the intake system.

[TownsendsFJR1300]

Yamaha US' thought is that if the motor did not need the vapor recovery kit in the first ten years of its life that if there is a problem after the 10th year it more than likely is not related to the failure to restart in a hot condition.

Also, there has to be some time limit to helping folks out. Otherwise the corporation would go broke. Trying to be all things to all customers. And all Yam owners would then suffer.

.

I can tell you, Yamaha motorcycle division had/has a a re-call on certain bikes back in 04 and 05, the TPS going bad.

My 04 FJR1300 was one of them (I didn't have any issues bit got it replaced anyway)

As of right now, if you have one of those bikes and the recall has not been done for some reason, Yamaha will STILL swap out the TPS FREE. We're talking 11-12 year old engines...

[boscoe99]

I can tell you, Yamaha motorcycle division had/has a a re-call on certain bikes back in 04 and 05, the TPS going bad.

My 04 FJR1300 was one of them (I didn't have any issues bit got it replaced anyway)

As of right now, if you have one of those bikes and the recall has not been done for some reason, Yamaha will STILL swap out the TPS FREE. We're talking 11-12 year old engines...

Recalls are open almost forever, if not forever. Take the F200/F225 recall to fix a throttle issue for instance. Yamaha will still fix that on their dime for the very first F200/F225 offered in 2002. Even for the tenth owner.

The hot restart condition was not the subject of a recall. It was just a simple product improvement. It was not related to a defect, safety related or otherwise.

[rodbolt17]

and the hot restart was typically a relief valve failure.
however YDS did not see it so the ECU must be bad.
I will guarantee that the early charcoal canister that vented to the atmosphere and later replaced with a canister vent valve had nothing to do with hard hot restarts and everything to do with EPA compliance.

the early F200/225 used a VST vent valve that would keep vapor in the VST until the VST internal pressure exceeded about 7 PSI. then the valve would open and allow vapor into the airbox until pressure in the VST went back below about 7 PSI.

this valve was an al body and tended to corrode internally due to moisture.
then it leaked and allowed all vapors into the air box.
this made for a very rich hot restart.
sometimes so rich the only way to restart it was by advancing the throttle and allowing more AIR.

hard hot restart can also be an ISC valve failure.

[bobterisch]

Vapor lock..? F225

Hi all,
I would love to see pics of that fan mod. I have he same problem. I would like to ask you all a question about the relief valve that goes into the air box that rod talks about. Usually when I can't get the engine to hot restart I squeeze the build strongly, if that don't work I vent the VST by pushing the Schrader valve, that works every time. Last time I had the hot restart problem I pulled the hose off of the VST side of the the relief valve. It had a lot of pressure and also shot out some gas. Is this to be expected? I left this disconnected and the engine restated with out a problem although some gas did continue to spurt out. When I put the relief valve back in to the VST hose but not into the air box I could see that it was allowing bubbles to come through.
I Have the hot restart problem every time after a run and either idling or drifting. The engine has 750 hours, new racor filter, new f filter, new on engine water seperator filter, new VST filter and new low pressure fuel pump. When I changed the filters this year I cut them all open and the fuel system was very clean including the VST tank.
Thanks for your replies

[rodbolt17]

fuel spurting out the VST vent is a sign of an incorrect float level or a leaking needle valve.
and yes it will cause an over rich hot restart.

[bobterisch]

F225

Thanks for the reply. The spurting fuel was from the tube with the relief valve removed. With the relief valve installed and pulled from the air intake I can hear it venting vapor from the VST. Rod when the relief valves failed did they faile by becoming clogged or becoming open?
Thanks

[bobterisch]

Valve

Hi
Installed new VST relief valve (air orifice). So far it seems to have fixed the problem.

[Doggydog]

Hi Bob/All- having trouble identifying the part number for the VST relief valve that solved your fuel issue. I have an ‘04 F225 TXRC that is dying at idle and I suspect this may be the issue you had. I have inspected lines, the bulb, the filters leading up to the VST.

any help with this part number?

[fairdeal]

I have an 04 F225 TXRC that is dying at idle

doesn't sound like 'the hot restart' issue to me.

If you want to eliminate any possibility of that being an issue,
disconnect the VST vent hose from the airbox,
add a bit more tubing to it,
and run it completely outside of the cowling -
maybe through one of the bottom cowling drain grommets.

Subsequently you can move on to determining why it is dying at idle.