4BY2 fuel explosion (sort of)

[JerryE]

I had the factory service done to replace the heater hoses on my 2009 R25 which has a generator. After that I launched and she started right up and ran for about a minute and quit. She would not restart, and I discovered large amounts of fuel spraying out from the gasket on the spin-on fuel filter on the engine each time I tried to start. The filter's rubber gasket had deformed (looked like a hernia), so I took off the filter, reseated the gasket and remounted the filter. She started up and ran for less than a minute and then sort of exploded fuel from the filter again and the engine died with the loss of fuel pressure.

It appears to build up pressure (? due to a blockage in the fuel feed or return system) upon starting which is released at the weak point in the filter gasket to the point where it can deform the gasket and blow out fuel into the engine compartment. Fuel valve is on, of course, from the filter in the generator compartment which feeds the engine filter in question.

Maybe the Yanmar mechanic (who took off the big black electrical Panel box on the port side of the engine) while replacing the heater hoses somehow pinched the fuel return line? Its back at the mechanic's who could not see a problem so, of course, they are calling the distributor. Can anyone advise who had a similar issue?

 

[PhilR]

Oh boy! My hoses are being replaced tomorrow.

 

[JerryE]

Well, Alto is still in the shop–now up at the Yanmar distributor's location in Middleboro, MA. They have determined that the high pressure fuel pump is not working properly. Get this: there are no spare high pressure pumps in North America. The good news is there are three in all of Europe. One is supposedly on its way to the distributor. These pumps rarely fail, but I suggested Yanmar might want to have, say, one pump in stock for all 4BY2 engines in America, just in case.

They do not want to pull a pump off a standby engine as the engines are run on a dyno to "break in" the parts so they all work together. This, reportedly, makes the pump unique to each engine...

Anyway, I'm waiting to hear when expedited shipping might have it arrive in the US. It has to go to Georgia, through customs for duty tariff, etc. before it can be UPSed to Mack Boring. They say they are doing everything possible. Furthermore, there is no guarantee that this is the cause of my actual problem of high back pressure in the fuel supply system; she's only at about 52 hours. I don't know if I'll even get the boat in the water this summer at this point. I'll keep you, dear readers, posted as this could happen to you too.

 

[knotflying]

So, when your new pump comes how will they dyno the engine so that the your pump will be "unique" to your engine. Sounds like a little bit of a crock to me, but I must say Mack Boring seems to know their stuff.

 

[JerryE]

Hey Mike,

I know, the "crock" part occurred to me... The stuff about the dyno came from corporate Mack Boring folks (who are well trained in the engine having torn them down and rebuilt them personally) not from the local guys in Middleboro, MA. I guess they are saying the pump leaves its unblemished newborn date and "becomes one" with the engine on the dyno. Maybe it's harder for a previously burnt in pump to adapt to another engine, than it is for a newborn... Sounds like the stem cell debate to me.

I don't know. They think the new pump will arrive early this coming week and they managed to bypass Georgia and have it sent it directly to Middleboro. So that's quick enough not to hassle them about pulling a pump off another engine–which they do have in stock. Got to pick your battles, so to speak. My biggest concern is whether this is even the basis of my problem; i.e., if the new pump will solve the fuel issue. I'll keep ya'll posted.

 

[Snug Tug]

Since the problem occurred immediately after the hoses were replaced it would seem likely that something (unrelated to the hoses) was disturbed during the work that caused the problem. Otherwise it's an amazing coincidence for the fuel pump to fail on it's own at that particular time. As to the run in of the pump with the engine, I think they mean that they adjust the fuel injection system (pressures, timing, etc) as a complete unit before and after the run in. If you put in a new pump, it might produce a slightly different pressure or flow which would require recalibration of the common rail system as a whole to get it back to spec.

These kinds of problems are very frustrating. I feel your pain! We have to be nuts (tug-nuts?) about boating to put up with these kinds of issues that crop up, usually at the most inconvenient time.

 

[JerryE]

Jon,
You're right. This is my therapy source as no one else in the world would understand our issues with "boat withdrawal." Only here can we seek support. Frankly, one feels a little silly (in the economic day and age) complaining that my yacht is broken... to the average bloke on the street.

 

[rt11002003]

Jerry E., when our children were young they called yachts

YAKS

. 🙂

No stigma using the word YAK. 😉

gene

 

[JerryE]

OK, then I'm bummed my Yak ain't working at the moment! :cry:

 

[HRowland]

"No stigma using the word YAK."

I think you will need to come up with another name. There are a number of YAK aerobatic airplanes flying in the US, such as the YAK 54.

http://en.wikipedia.org/wiki/Yakovlev
http://www.yak.ru/ENG/PROD/current_54.php

Howard

 

[rt11002003]

One will have to talk to the children about the use of the word "YAK'. 😉

The Soviet Union Yak aircraft goes way back, as do the children (born 1962). I think the Yak goes back further. If memory serves me the USAF engaged them in the Korean conflict. I didn't join the USAF until 1955 so I don't have first hand knowledge.

gene

 

[JerryE]

Jeeze, only on TugNuts would there be someone obsessive enough to debate about the use of "Yak." But, then that's why I read everything written here, for such tidbits of useful trivia.

 

[bbrh842]

I lamented because my Yak was broken, until I met a man who had no Yak.

 

[abcandjrc]

"They do not want to pull a pump off a standby engine as the engines are run on a dyno to "break in" the parts so they all work together. This, reportedly, makes the pump unique to each engine..."


"So, when your new pump comes how will they dyno the engine so that the your pump will be "unique" to your engine. Sounds like a little bit of a crock to me, but I must say Mack Boring seems to know their stuff."


My suspicion runs to this: They do not want to have to remove one pump, install two, bleed two, time two, and adjust two when all it takes is making you wait a bit longer and they can do less than half of that. I tend to be a skeptic, but a skeptic who has built several high-performance automotive engines.

But like they say, "Don't mess with the cook or the paymaster!"