Information to Mercruiser 7.3 d-Tronic

[SeaRay290]

Hi, my name is Patrick and I come from Germany.
I have a SeaRay Sundancer 290 from 1998. The engine is a Merc 7,3 v8 d-tronic also from 1998.
A few months ago my Boat dont want to run its top speed.
When accelerating, the engine speed increases to 2700 rpm. However, after a few seconds they drop down to 2000 rpm.
The engine is a Mercruiser 7.3 d tronic from 1998. Boat is a Sea Ray Sundancer 290 also from 1998.
Does anyone here know of such problems?

I think its something with fuel supply, fuel pump or something like that.

Maybe there is someone here in the forum who knows about the engine. Also regarding the diesel pump. Which pump is installed and what alternatives to the installed pump are there? Unfortunately I can't find anything on the German market.

Need your Help

 

[spannerman]

The high pressure injection pump is under the oil cooler and charge air cooler between the two cylinder heads at the front of the engine. There is no alternative pump for this engine. There is also a lift pump between the heads towards the rear of the engine, parts are getting hard to find now, the engine is by International Harvester in the USA.
I would check first that there is no air getting in from a loose hose or pipe, and get a workshop with the Rinda diagnostic tool to check there are no fault codes in the system.

 

[SeaRay290]

First of all, thank you for the quick response.
I guess it's not the high pressure pump. Much more something with too less fuel. I would like to replace the lift pump, but I can only find these pumps for the small Mercruiser engines like the 2.8L, 3.6L, 4.2L.
The error only occurs under load; the engine runs normally when idling.
In the spring I change all the filters when I find the lift pump with the hope that the problem is fixed.

Again about the lift pump, are there alternatives like Ford etc?

I'll be at the boat next weekend. Should I take a closer look at something beforehand?

I think i need something like that attach file

 

[spannerman]

In the parts catalogue the lift pump is mechanical but does’t look like the picture in your post, its cylindrical and sits down between the heads under the air cooler and is no longer available from Mercruiser. You may find one in the US from another supplier as its a well known engine there. It does sound like fuel starvation, I have experienced this with air leaks and weak lift pumps. You can see what it looks like on RavnsGarage.no parts page.

 

[jointventureII]

In my lift pump on a 4.2 mercruiser diesel, there was a mini filter which was clogged.

I was getting to about 3000rpm before the engine wouldn't hold revs and dropped to about 2000.