Yamaha 225 turw - 1998 - stalling at above 4500 rpm

[DMAHLER]

Has anyone experienced the problem of a usually well running and well maintained Yamaha 225, that starts, idles fine, will run all day long at anything up to about 4400 - 4600 rpm, and then sputters for 2-4 seconds, and stalls. It will immediately start right up again, and run until that max rpm is reached, then stall. this is a dual engine install, and the other motor runs perfectly, so fuel is all ok.
have checked the keyswitch kill switch, adn even swapped the connectors to the other motor, yet, problem still exists.
any help is greatly appreciated.
thanks guys

 

[rodbolt]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

sounds like a fuel restriction,bad lift pumps or a clogged VST filter.
thats the exact symptoms of low fuel rail pressure.
keep doing it and you may get to post about detonated pistons.
when was the last time the lift pumps were replaced?
the last VST service?
the last O2 sensor cleaning and TESTING?

 

[DMAHLER]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

THanks, i just ran to the local Yamaha dealer, and dropped the 300.00 on the new vst filter and gasket. will test out the boat in the morning and let you know. the vst filter had some specs of debris on the bottom of filter, and some clumps of crud in the housing... maybe it clogged the needle valve??
in any event, the entire housing was sprayed clean with carb cleaner, air burst dry, and carefully reassembled with hospital clean hands and tools.
will reinstall in the morning.
thanks,
dave

 

[DMAHLER]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

After changing out the vst filters, and complete scour and hospital style cleaning of the vst, reassembly, and test run... same problem, engine runs fine, but only up to 4500 - 4600 rpm, then turns off... give the constant fast beep at key-switch... and will immediately restart.... but stall again if i get up to that 4500 - 4600 rpm range.

note- that the old vst filters were not really that dirty... some evidence of particles, but not bad at all.

also- i cleaned out (carb cleaner) the check valve that is just before the vst case.

any help is greatly appreciated.. i am wondering if it will make sense (probably) to swap the vst;'s between the 2 motors and see if problem follows the vst?

also- i swapped the fuel in lines, so safe to say that the problem is in THIS engine, and its inside the engine, not before it in the fuel line.

Thanks for your input/guidance/opinions.....

 

[rodbolt]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

you wish to F*** up two motors,drop cash and wont answer some simple questions first.
good luck.
wish you was my customer.

 

[DMAHLER]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

rodbolt- i apologise, did not see your initial response.
the answers are:
i have no record of service on any of these parts (vst/lift pumps/o2 sensor)

the "trusted dealer" that Yamaha tech support sent me to, told me that he would "bet his life" that it was the vst filters,.... I trusted his word, and bought the filters, and gaskets, ran home and changed them. as you read, same results.

i suppose it quite possibly can be the lift pumps (looks like there are 3) or the o2 sensor (not sure where that part is.??)

the "trusted " dealer, is now saying that it may be the throttle position control module??, and wants me to bring him the boat - which is a huge problem.

I am sure it must be some stupid little thing that I am not looking at yet.... what would your recommendation be to do?

thanks,
dave

 

[DMAHLER]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

1 more question... is there a way to add fluid to the power trim system, seems like its low, making gurgling sound, and not as fast up as the other side... pump seems to be turning fine... just gurgling as if low on fluid. if possible- WHERE IS THE PORT TO ADD?

 

[DALE BRATTON]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

has anyone experienced the problem of a usually well running and well maintained yamaha 225, that starts, idles fine, will run all day long at anything up to about 4400 - 4600 rpm, and then sputters for 2-4 seconds, and stalls. It will immediately start right up again, and run until that max rpm is reached, then stall. This is a dual engine install, and the other motor runs perfectly, so fuel is all ok.
Have checked the keyswitch kill switch, adn even swapped the connectors to the other motor, yet, problem still exists.
Any help is greatly appreciated.
Thanks guys

fuel flow- fuel flow- revlimiter malfunction

 

[DALE BRATTON]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

90 percent chance ats a fuel flow- having a friend pump the fuel ball - w/o falling out of the boat- when you get to 4400 and see if its soft and it improves when you pressurize it a bit- if so its fuel flow-- other is rev limiter problem fro water sensor- or pressure sensor- or oil sensor will reduce rpm and not let you run full throttle.

 

[DMAHLER]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

THANKS DALE- there is no fuel bulb, boat has electric fuel pump.
als0- is there anything indicated by the constant fast beep when it stalls?
are there any "tests" for the sensors that you think may be the culprets????

 

[rodbolt]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

there are NO sensors assoiated with ANY rpm reductions.
TPS,NO throttle position control, can be easily tested with a digital or an analog voltmeter.
digital is more accurate but the analog will catch anything intermittant that a digital may miss.
the lift pump should be replaced every 3 years.
the O2 sensor maint is every 200 hours OR yearly whichever occurs first but doesnt sound like your problem.
the fuel rail pressure can be monitored at the problem RPM and load, should stay above 35 PSI at any RPM.
that system uses a DEC switch,means if one engine goes into RPM reduction so does the other, also means if one engine stalls the alarm sounds to alert the operator that an engine stalled.
for what ever reason your describing a lack of fuel,and oil, in the intake tract.find it and fix it before the detonated piston due to lean running post.
the lift pumps can be easily replaced,remove and gut or replace the check valve between the engine filter cup and the lift pump intake.
use the yamaha boat in a box,or equivalent to test fuel system vacum to find restrictions.
its an electric pump with a flow meter a vacum guage and a throttling valve in a little box.
works wonderfully and the key never has to be one.
its considered an essential tool and was sent to al yamaha dealers.
not all know how to use it or when or why.
electrical failures on yamaha are rare but do happen,hoever fuel system issues are common,easy to eliminate and can pop a piston if not found and corrected quickly.

 

[99yam40]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

THANKS DALE- there is no fuel bulb, boat has electric fuel pump.
als0- is there anything indicated by the constant fast beep when it stalls?
are there any "tests" for the sensors that you think may be the culprets????

It sounds like you do not have a Yamaha service manual for your motor. It would save you tons of time and money to invest in one. It will have step by step procedures and what equipment in needed to troubleshoot and repair.

How do you prime the fuel lines and work the air out when you change the filters and pumps if there is no primer bulb? The electric pump would have a hard time sucking on air to pull the liquid fuel into the system.

I am not sure I would call this a well maintained 1998 Yamaha 225, if there are "no records of service on any of these parts (vst/lift pumps/o2 sensor)"

 

[rodbolt]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

quite a few grady whites, and some other hulls, installed an electric primer pump operated with a momentary on switch instead of a primer bulb.
when its acting up hit the switch, if it helps its not a motor issue but a lift pump or hull fuel system issue.

 

[DMAHLER]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

hitting the elect fuel pump may not have worked... was not able to fully test. can anyone advice WHERE the lift pump is located, as perhaps that's the next to replace parts, since this seems to be the most likely culprit, and I don't think its been changed for perhaps 5 years.
also- any way to add power trim fluid to system?
thanks gentlemen, you have all been a great resource!

 

[rodbolt]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

the 3 lift pumps are located on the port side of the engine.

 

[DMAHLER]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

AND THE O2 SENSOR?

and.. can u add fluid to power trim system?
thank you!
dave

 

[rodbolt]

Re: Yamaha 225 turw - 1998 - stalling at above 4500 rpm

O2 sensor is on the upper aft end stbd on the block.
to add fluid raise the engine,remopve the 17mm hex plug and add fluid to the bottom of the threads.
you really really need to read the service manual or you ARE gonna tear something up or hurt yourself.