Second Yamaha 115 four stroke this year.

[texinutila]

Anyone know about power loss problems occurring on brand new Yamaha 115 four strokes. The dealer, in Tegucigalpa, Honduras is not a credible resource, just replaces them. The first one stopped firing on cylinder two during the break in period, and the replacement will now no longer go past 3400 rpm and roughly at that. This started after about 70 hours. It also seemed to coincide with some bad fuel that went around the island. (Utila Honduras). Fuel lines and filters are ok.<br />Is this common with this engine, or does Yamaha just send all the seconds to third world dealers.

 

[rodbolt]

Re: Second Yamaha 115 four stroke this year.

hello<br /> carefully test all the normal things ,plugs ,TPS voltages but if you suspect fuel open up the vst. if the high pressure pump filter is nasty odds are the injector filters are as well. each injector has a filter that can clog and reduce fuel flow. <br /> so far yamaha does not give any flow or pressure drop tests. I have used a resistor in the temp sensor circuit to make the injector pulse width longer making the engine richer. if that makes it run better then start pulling injectors. there are shops that specialize in injector flow testing.<br /> good luck and keep posting

 

[Greengilz]

Re: Second Yamaha 115 four stroke this year.

I had similar symptoms to this but far more extreme. Both our motors gradually slowed to 3500 rpm. Turned out to be fuel blockage in the filters before the injector pump and in the injectors (dirty fuel). I didn't have a Racor prefilter fitted but kept the filter/water on the motors clean. Microscopic inspection showed particals as large as 100 micron blocking the injectors. EFI fuel injecton specilists I have been dealing with say EFI cars have pressure filter down to 5 micron just before the injector rail. Honda outboards appear to have an appropriate pressure filters but Yamaha don't seem to have learnt yet. We had our filters replaced, fuel system & injectors cleaned, and 2 micron Racor prefilters fitted. 200 hours later my motors were wore out with water & fuel in the engine oil. Turns out some particals left over afer the cleaning got into the injector(s)and then injectors leaked fuel into the cylinders and crankcase every time the motor was turned off. Remember it only takes 1 particle of dirt to do this. As the majority of my motor hours are trolling and I swap over motors frequently the fuel diluted the oil very rapidly over a 24 hour non-stop trip. The other issue which contributed to the motor wearing out was inadequate oil cook-off from all the slow speed trolling and emersion of the oil pan. The oil does not get hot enough to cook-off the normal combustion volatiles (including water). The water adds corrosion errosion wear to reduced oil viscosity wear. The motors also have blind cavities under the block which capture and hold the water vapour which turns to sludge. <br />I think my problems were caused by fuel filtration not suitable for the purpose intended and outboard not suitable for purpose intended.<br />No help from Yamaha in this part of the world so I will buy Honda next time.

 

[rodbolt]

Re: Second Yamaha 115 four stroke this year.

greengilz<br /> honda has had similar problems.<br /> they cannot design a motor for all applications. most fuels have an internatiuonal standard for particulate matter. dirty or poor quality fuels is not a design problem. that is why I tell people to insure the t stat is good and the cooling system is kept in toip shape. and the motor needs to be run at or near WOT for 30 min each trip. preferably on the way home. the motors need to be trimmed 10-15* positive for storage to prevent oil drainback past the rings. 4 stokes have problems not asssociated with 2 strokes. most people baby them to much cause they keep thinking its a car not a high performance marine power plant that all it has in common with a car is it burns gasoline. 90%of the problems I deal with is customer induced. you would not belive how many ten hour checks I do where the motor has not exceed 3000 rpm for the entire breakin. I did one last week that did 10 hours below 2000 and none above. I noted the improiper breakin on the workorder. the leaky injectors can be very easily found with a simple fuel pressure gauge,a little experience and a stop watch.<br /> good luck and keep posting<br />ps watch the fuel system vacum with 2 micron filters. as the tiny filters clog it will cause a lean condition and your next post will complain of burned valves.<br />it should be against the law to rig a boat without at least a 10 micron water seperator but seems most engineers dont expect boats to get wet.

 

[rodbolt]

Re: Second Yamaha 115 four stroke this year.

after rereading green gilz post it seem that he idled the motors for 24 hours? if he did that is so far outside the design parameter of raw water cooling its not funny. to help prevent the buildup of scale and minerals the seawater temps have to be held close to 150*. at low speed the block temp may go even cooler. if you must idle that long then seawater cooling is not an option for you.<br /> good luck and keep posting

 

[gss036]

Re: Second Yamaha 115 four stroke this year.

Rodbolt, I think he is saying that the fuel was going into the oil for 24 hours while the boat was sitting, not running. Yammy has had that problem for years w/4 stroke engines. Even w/ carbs, gas keeps leaking into the cylinders and past the rings into the oil.

 

[rodbolt]

Re: Second Yamaha 115 four stroke this year.

if the carbs are ok they will never leak gas past the butterflies. if the carbs are leaking its a customer maint issue. means they knew it was running poorly and ran it anyway. same as the injectors. most engines built by yamaha cycle the injectors once at shut down to bleed off the rail pressure. even if one drips a bit there is no pressure on the rail and therefore not that much fuel will escape.I am thinking the problem is someplace else. if the injector leaks while running the motor will idle like crap. if a motor is telling you its sick and you run it anyway call a priest. it will die.<br /> good luck and keep posting

 

[Greengilz]

Re: Second Yamaha 115 four stroke this year.

Thanks Rodbolt, I didn't realise the injectors cycled on shutdown. Is this a recent change to the ECU, our motors are 2002 model, 2001 manufacture. If the ECU dumps the pressure from the fuel rail on shut down how can puting a pressure gauge on the fuel rail tell you anything. I agree with you about restricting the fuel suction line but there are fine filters with extended surface area that have less pressure drop than the course filters - buy big and quality. http://www.yamaha-motor.com/accessories/otb/fuel01.html sums it up well and is an admision that their EFI & DFI filtration is inadequate. Anyway this filtration is rz about face - fancy having filters getting courser as it gets closer to the critical parts. Take a look at an EFI car to see how it should be done. 35 microm before the mecahanical pump, 25 microm before the injector pump, 5 micron before the injectors. The 5 micron filter protects the injectors from the fine stuff that can effect the injector spray patterns and shut-off, catches wear particals from the injector pump and the little black bits that benzine and other lead subsitute fuel additives seem to disolve from the fuel system. The 5 micron filter is a pressure filter that costs about $NZ10-$20 (US$5-$10) This apears more money than Yamaha can afford to spend on their F115s but Honda seem to manage to afford the pressure filters. EFI Cars & EFI Honda outboards have them and don't have ("as many")fuel in oil problems. Yamaha doesn't have them and has a high incidence of fuel in oil problems (over 50 cases on the web I have found so far)<br />You ask how can the fuel leak into the engine if the rail pressure is blead off - well the same crude that effects the injectors effects the fuel pressure regular shut off which then vents to the VST tank. We have photos of the clean patches in the bores where the fuel has ponded before leaking past the pistons (engine stopped). We have done the sums - our last oil test had 3% fuel & 3% water, (from 15 hours running) thats 3% of 4.5 litres = 135 ml, the fuel rail hold 30 ml of fuel, thats like turning the motor off 5 times. You seem very experienced but keep an open mind and think about. <br />We have legislation that controls fuel octane, additives and everything else but not particulate levels. Our service stations have a mix of 50 micron strainers and 30 micron filters.

 

[rodbolt]

Re: Second Yamaha 115 four stroke this year.

there is also a filter on the high pressure pump that should be serviced. its terrible to get to and expensive as well. maybe in your area or with your tank set up there is a problem. the motor should have idled poorly with that much fuel leaking. the pressuree regulator on that engine is all mechanical and only serves to maintain 35 psi or so in the rail. at acceleration the ecu senses the throttle angle change and opens the pulse width as well . the sudden pressure drop acrossed the rail is compensated for by the vacum signal on the regulator. I have seen regulators fail causing rich running. like I say. the dirty injectors is not a yamaha warrenty issue. I wont sell a motor if I dont rig it and I wont rig it without a good water/fuel seperator even though I cange 4 or 5 a year that just rust holes through them. that would be due to excessive maint. the EFI technology used is very simple and straight fwd, the injectors and pumps and such are antique tech. I hope yamaha gave some assistence but I dont know how customer relations are in NZ. good luck with them and keep posting

 

[Greengilz]

Re: Second Yamaha 115 four stroke this year.

We are very particular with our cars and boats and are fanatical with servicing. Our EFI cars have done over 300,000 km and we expect 600,000 km of trouble free motoring before we sell them. We expected similar longgevity from the EFI outboards and may have got it if the motors had proper fuel filtration or if Yamaha said that a prefilter must be fitted anywhere in their installation information. Fuel contamination is not covered under the warranty. However Workmanship is very much a warrantly issue. Poor or inadequate fuel system design is bad workmanship and very much a warranty issue. EFI cars have been around since 1956 don't have these fuel problems because they have properly designed fuel filtration systems. Putting a prefilter before the outboard is good practice but it should be designed and specifed by the outboard manufactured as only they know what is an acceptable suction pressure drop for their pumps. There are several threads on the web where the F115 fuel pump diaphams have ruptured at very low motor hours which go to suggest the outboard manufacture should recommend or supply the prefilter. The prefilter is the bandaid - the real problem is the f115 fuel filtation. You still get crap in the injectors even with a prefilter fitted.

 

[rodbolt]

Re: Second Yamaha 115 four stroke this year.

only if you use crappy fuel. the VST has a filter inside it. have you ever serviced it? this is not a car. I dont care what the salesman, said but the injectors came directly from the automotive side. I am sorry your fuel quality is so poor. next motor you buy you may need to write the engineering dept and ask them what to do if you insist on running nasty fuel.<br /> good luck and keep posting.<br /> PS post back about the high pressure pump filter

 

[Greengilz]

Re: Second Yamaha 115 four stroke this year.

The issue is not crappy fuel. The issue is any contamination what so ever. EFI fuel injectors have zero tolerance for particles of contamination above 5 micron. Fuel systems have to be designed to take the crap out of the fuel. Have you ever cleaned out a fuel tank to find it perfectly clean? I bet not. All supplies of fuel have contamination to some degree. Your aluminium fuel tank makes its own contamination by forming aluminium oxide particles. Dust gets around the fuel fillers and vents every time you drive down a dusty road. Yamaha put cheap mild steel parts in their fuel systems that rust and introduce rust particles into the fuel system - just look at the pressure regulator for example. Sure, fuel filters block, thats what they are designed to do. They are also designed to be easly and regularly changed (with the exception of the Yamaha injector pump filter. No, I have never changed this filter my self but I have paid the professionals to do it for me. There was crap in it but the biggest problem was the crap that got past it to block the injectors. The injectors have a little inlet screen about 20 sq mm in size to catch the odd larger bit of dirt that might get in during servicing. A proper pressure filter (before the injectors)has 6 sq metres of surface area to catch the crap. That mean it takes 300 times longer to block a pressure filter than to block the injectors. If you block the injectors in a hazardous marine situation - You die!! That means you have a 30,000% better chance of living if Yamaha put a pressure filter on their F115.

 

[Greengilz]

Re: Second Yamaha 115 four stroke this year.

We have anylised the particulate matter from our injectors to be 9 to 100 micron with the bulk of the particals around 50 microns. You ask to any EFI specialist if this filtration is suitable for EFI. Watch out when specifing filter micron ratings as specifing 5 micron filter for example does not mean it will collect every particle above 5 micron. Generally you have to go significantly finer to collect 99.9% of 5 micron particals and larger.

 

[seahorse5]

Re: Second Yamaha 115 four stroke this year.

Yamaha had some filter plugging issues on EFI and HPDI motors due to the copper from the brushes and commutators on their electric fuel pumps. For '04 they changed to carbon brushes since the carbon dust has smaller particles that will pass thru the injector screens.