new 5ph 4stroke, gas in oil, what to do?

[TOHATSU GURU]

Re: new 5ph 4stroke, gas in oil, what to do?

Garyn,<br /><br />My advice and suggestions(and most everyone else's), are based on what we have all come across over the years. It would be very odd to have a new engine that has a problem with a fuel pump diaphram. They tend to go bad due to age(think in terms of 5-15 years). Is it possible?....Yes, one out of 10,000 maybe. And that would be from damage to the diaphragm during its original installation. We haven't heard back from JJerry in quite sometime. It's probable that the situation has resolved itself by now and that his engine is running correctly. I have yet to see one of these oil/fuel dilution problems that was not caused by:<br />break-in<br />low rpm<br />synth oil<br />or<br />freaking cold weather...<br />Of course the day just started and I'm sure I will have one before noon.....now.

 

[garyN]

Re: new 5ph 4stroke, gas in oil, what to do?

Elvin<br /><br />I see your point but - the most likely cause of this gas in oil condition is the engine pumping the gas into the oil. I understand that the mechanical fuel pumps will all do this if the diaphram is bad. Was mine bad from install, maybe? but that is why I took it in under warranty 4 times. My engine is a 2001 with about 200 hours total on it and regular oil changes. It is used in warm Southern California and never saw synthetic oil.<br /><br />I wasn't trying to put down common sense suggestions but - it damages engines to continue to run them with diluted oil. The experts say even a 5% dilution can reduce the life of the engine a lot.<br /><br />What I am really put off by is the assumption that these parts last years (so why check them) and the idea that most of us don't know to open the air vent on the fuel tank or disconnect the fuel line during storage. I have owned about a dozen engins in my life time and learned a lot about looking for the logical simple solutions. However, that should not keep a dealer from really listening to the owner and looking deeper.<br /><br />These engins are a pain to put on and take off a transom and I have done it now 10 times.<br /><br />What do you think about my concern that the engine was run hard with the diluted oil (say 4+hours) and now I hear a sound that makes me think the bearings are damaged? Would you want to keep running this - or be comfortable selling ti to someone else? <br /><br />All I want is a good,safe reliable engine that give me value and peace of mine. I run at night between San Diego and Catalina and that is not the place to have to paddle home.<br /><br />Just wondering and thanks for the input.<br /><br />Gary N

 

[TOHATSU GURU]

Re: new 5ph 4stroke, gas in oil, what to do?

Gary N,<br /><br />I was really hoping that I could edit my post before anyone read it. I was factually incorrect about this model range engine. So here goes. I just had a rather lengthy discussion about an hour ago with the National Service Manager (O.K. Garland I'm giving you credit) for Nissan/Tohatsu about my earlier response. While its true that fuel pump diaphragms on new two-stroke engines don't fail, failures do occur much more frequently on four-stroke engines. The reason for that is that the type of fuel pump diaphragms used on this range of engine has a hard center section that can tear loose from the rest of the rubber. It is caused by pressure build up from leaving the hose attached as an earlier post from AG indicated. As I was just lectured by "Him Who Knows All" that the pressure can reach 50 PSI or higher, I have to say that diaphragm failures could certainly be a much more common problem than I thought. <br /><br />But, every four-stroke engine that we have ever done oil changes on have at least some fuel contamination. Out of the 2000+ that I have been associated with not one has had a diaphragm failure. That may be because we lecture our customers about running the gas out of the engine when they are done for the day, so our customers do not fit the criteria for this type of problem. Your case, while not unique, is still not representitive of the average consumer using this size range of engine. You do have a point about assuming that the diaphragms last years and not checking them when the engine is having a problem with fuel dilution. I know that we will check them in the future if anyone continues to have the problem after we have educated them about excessive idling. <br /><br />As to why a dealer does not check the diaphragm off the bat. That's easy...dealers are not paid by the engine manufacturers(all brands) to check for potental problems. They are only paid to repair or replace a defective part. Imagine if you would a dealer submitting a warranty claim to tear an engine apart to check the ring gap on a piston ring...and then finding that it is within the correct tolerance. That dealer's claim would be laughed at all the way to the trash can. It only takes a couple of minutes to check the fuel pump, but where do you draw the line on the perception of a problem. Again, in your case, it should have been checked at some point( I would like to think that WE would have caught it on your second complaint ) but, you really can't overlook the most likely cause as the problem.<br /><br />As to possible damage. Yep, could be. If you are hearing a noise that did not used to be there you could be in for a premature failure. You are obviously not stupid and know a lot more than the average consumer does. Trust your intution.<br /><br />And finally...your right. Service personnel should pay more attention and dig deeper. The old adage about "not doing it, if you don't do it right" really is true. While we aren't the dealer that let you down, it does reflect on the industry as a whole. I've heard your message and I've made others aware of your legitimate concern.

 

[garyN]

Re: new 5ph 4stroke, gas in oil, what to do?

Elvin<br /><br />Very good reply, thank you. I do want to point out that I do run the engine dry after every use!<br /><br />I do appreciate your concern as the value of these engines is so tied up into the custonmer service division of the company. Sure, most are good and those people love and rave about the product, but get a bad one, a weak dealer and inactive mfg. rep and you go crazy, waste money and feel insulted.<br /><br />I believe that the fuel pump on my engine was bad from the get go - maybe only a pin hole so it ran OK most of the time. Now, I really cannot trust the engine. When the dealer gave it back to me last time and wrote that "customer overfilled engine with oil" and I told him that was impossible he still insisted it was "fixed" I took that engine to the boat and ran it - when it stalled, backfired, smoked and acted really badly I kept trying to run it. Why because I was checking for all the easy things like my fuel lines, air valves, depth of engine on transome etc. because the dealer was so sure it was perfect (and he ran it in his tank, I assumed).<br /><br /> Then when it stopped hard and I took it back again they did not understand that the advice and service they gave me added to the damage to the engine. They ran it more and tried to adjust the carb again for about a half hour. Only after they gave it the "torture test" and it smoked like a 15 year old two stoke did the look at the oil again - and it came out of the dip-stick opening again. <br /><br />Really bad, also I note that all the guys here are really biased towards the "old two strokes". I guess that is why they keep blaming the carb for everything. <br /><br />Again, thank you and I wish I would have my work done by a guy thoughtful enough to go into the details you did.<br /><br />Gary N.

 

[TOHATSU GURU]

Re: new 5ph 4stroke, gas in oil, what to do?

Gary,<br /><br />It would have been a little more helpful if you had said that this was a Yamaha 9.9 that you were having trouble with. I assumed that we were discussing a Nissan 5hp. I have no idea whether or not their fuel pump is subject to the same types of problems that could rarely occur on our 5hp.