Would you run this Di head?

[blairwill4]

How do I identify the difference between the two heads?

 

[ski-d00]

The casting will have a 585 in it on the underside will be gen 1 and I think it was only used on 2000(first year) and part of the second year(2001) DI models. All others through 2007 use gen 2. Gen 1 will have the black air injectors which are shorter than the newer gray style ones which are not interchangeable. Your cylinders will also have only 5 ports instead of the newer 6 port style.

 

[68ragtop]

The majority of DI rebuilds I do are from using the wrong oil and the failure will burn each cylinder down so when I see sudden low psi in both cylinders that's my first thought. A friend will borrow it and put the wrong oil in it and boom. The DI is the most sensitive to wrong oil since it relies on it more than any other seadoo motor for lubrication and cooling. The DI also uses the least fuel per hp than any other motor but certainly is oil rich as a necessity.

325 hours(and 15 years) is a lot for a stock DI motor and it is due for a rebuild. You should test the oil pump when tore down but they typically are very reliable. Low fuel pressure is not normally a reason for engine failure, typically it won't run or barely runs with a bad fuel pump. Changing the two filters in the bottom of the fuel pump is always a good idea but doesn't normally cause running problems.

Regarding your DI head, they made two styles so make sure you get the right one and they are not interchangeable unless you swap other fuel rail parts such as air injectors.

I have a lot of DI parts as well as BUDS(which does help in DI issues) and can help since I'm only an hour away from you. I grew up in Ft. Wayne and get there every couple weeks.

My findings of failure has been more from rusting bearings/crank failures, then debris gets up top & destruction ensues. But, I haven't done enough of them to give any statistics. DI's seem to accumulate more moisture in the case than other engines. Wrong oil sure could add to an already sensitive engine, no doubt. Not the engine to play oil games with. In fact I fog mine every time I know it might sit more than a day or two. Might be unnecessary to do it that much, but its cheap insurance on an expensive to rebuild engine.

Its worth noting If a fuel pump is getting weak, the wide open throttle pulls can have less fuel pressure resulting in leaner combustion. No question if the fuel is too restrictive it will get symptomatic as it starves for fuel like you mentioned & that seems to be the case with most skis talked about on the forum. But its the in-between stuff that sure could take out the top end. I just wouldn't say it can't happen, cause it could. I think most of these bad fuel scenarios are from skis that probably ran fine before somebody put them in a shed for many years on end, then the fuel going bad, or moisture gets into things.

IMO, Any drop in fuel pressure under acceleration & there is a problem lurking even if its running fine otherwise.


We really need to make a video of how these fuel systems really work for members with the DI's. Would be so helpful to guys with these skis. I don't have the slightest idea how to make a youtube video, but my nephew does. Might be worth the effort to get in depth on one?

 

[68ragtop]

How do I identify the difference between the two heads?

Actually the 5 port cylinders are the newer style (low emission, late 2002 & up) & the 6 port are the older 2000 to early 2002.

The heads look similar. The early style have a threaded cooling hose connection & the later are part of the casting

 

[jhjesse]

Actually the 5 port cylinders are the newer style (low emission, late 2002 & up) & the 6 port are the older 2000 to early 2002.

The heads look similar. The early style have a threaded cooling hose connection & the later are part of the casting

Yep all three of mine have the 6 port head. 2000gtx, 2001gtx, 2002rx. Good info.

 

[Sportster-2001-951C-Stock]

Its worth noting If a fuel pump is getting weak, the wide open throttle pulls can have less fuel pressure resulting in leaner combustion.

IMO, Any drop in fuel pressure under acceleration & there is a problem lurking even if its running fine otherwise.

So I'm interested in the fuel pressure issue of course, it should be 117psi at idle but does it remain that high through the entire throttle range?

 

[68ragtop]

At idle, the air regulator starts to open up at 78-80psi as it dumps the excessive pressure out of the rail. putting the fuel pressure at about 107. (80+27) As the engine RPM's rise, the air pump volume increases and the air pressure will rise slightly past 80 PSI in the rail & that in turn raises the fuel pressure by the same amount. Its not a whole bunch, but it definitely goes up 3-5 lbs as the RPM's go up.

Do you recall when I dead headed an oem fuel pump with a gage a few years back? That thing produced over 150 psi in less than 2 seconds of power. Actually caught me off guard & I was thankful the test line didn't burst in my face. Crazy strong little pump. it had my full attention & respect after that.

 

[Sportster-2001-951C-Stock]

At idle, the air regulator starts to open up at 78-80psi as it dumps the excessive pressure out of the rail. putting the fuel pressure at about 107. (80+27) As the engine RPM's rise, the air pump volume increases and the air pressure will rise slightly past 80 PSI in the rail & that in turn raises the fuel pressure by the same amount. Its not a whole bunch, but it definitely goes up 3-5 lbs as the RPM's go up.

Do you recall when I dead headed an oem fuel pump with a gage a few years back? That thing produced over 150 psi in less than 2 seconds of power. Actually caught me off guard & I was thankful the test line didn't burst in my face. Crazy strong little pump. it had my full attention & respect after that.

Okay, the fuel pressure should be about 107 at idle and shouldn't drop from there during operating, right?

I wasn't totally surprised the pressure shot up so high while dead-headed and agree you're lucky you didn't get a face full of fuel! These high pressure pumps are pretty cool inside, a couple I cut open were a little gerotor on the end of an armature shaft.

 

[68ragtop]

Okay, the fuel pressure should be about 107 at idle and shouldn't drop from there during operating, right?

I wasn't totally surprised the pressure shot up so high while dead-headed and agree you're lucky you didn't get a face full of fuel! These high pressure pumps are pretty cool inside, a couple I cut open were a little gerotor on the end of an armature shaft.

Yep, 107 at idle & only slight increased pressure with higher RPMS. This is RPM sensitive rather than load, so rev's on the trailer should show the same thing as being on the water. On a standard gage its hard to read at idle because the needle bounces with the pulses of the air pump. So the needle might be "vibrating' between 102- 112 ish for example, (25 pulses per second at idle) but the center of that vibrating range should be 107. I wonder if this is where another member was reporting a higher pressure at idle? reading the highest edge of the needle? Never thought to ask that until now. If its higher than 107 it could be a bad gage or there could be either a restriction in one of the return lines (air or fuel) or a bad regulator.

A liquid filled gage would be ideal for testing the fuel pump pressures to smoothen out the reading.

Back when I dead headed the pump, I had it connected to a 150 psi gage & hard wired the pump to a battery. luckily I was able to pull the wire back off before disaster. It wouldn't surprise me if they can produce more than 150psi. It groaned as the pressure went up, but it wasn't done when I pulled the wire. when I saw the needle shoot up I yanked the wire in a panic. Honestly was 2 seconds IIRC.

When I get my toys out for the summer, I think I will try to make a video of how the whole thing works. Might help guys just getting into these machines this summer? I have tap in tees for both the fuel & air lines. So maybe It can show the relation ship between the two.

 

[Chester]

Chester I'll take it. Your inbox is full so I can't pm you

Sorry but my head is junk. I found it yesterday and it looks like someone used a hand grinder to clean it up.

Chester

 

[jhjesse]

You can try Minnetonka here on the forum. He has good used parts and is great to work with.

Looking at your pic it looks to be a 6 port head, but I would verify before purchasing one.

 

[blairwill4]

Does any one have a hose diagram. I'm helping a friend with a different ski, Di xp put his motor back in and it's a mess and I don't know where a ton of the hoses go.

 

[Ankeneyou]