Merc 7.4 MPI splutters and excessive oil usage

Hi, I find my Merc 7.4MPI consuming oil - more than normal. When I start the engine, it smokes white a bit but nothing out of this world - only just as it fires up - and only after I havn't used the boat for 5 days or so. I read on this forum that the oil cooler may be leaking. How can I tell if the oil cooler is leaking without a pressure test? Are there any visible traces? Something which I should look for?

One more problem I have - which came up after I took the boat out of the water for the winter (no winterising done as I start the engine every 3 to 4 weeks), is that it starts OK and after a couple of second it splutters and start shaking - and it works fine for some seconds and starts spluttering again. When I increase the throttle it seems to works fine. What can the problem be?

Thanks - Jezz

Re: Merc 7.4 MPI splutters and excessive oil usage

I read on this forum that the oil cooler may be leaking. How can I tell if the oil cooler is leaking without a pressure test? Are there any visible traces? Something which I should look for?

Click to expand...

Ayuh,... Oil in the Exhaust Water....

As for the rest of your Problems,....
I would think a Full Srevice,+ Tune-up, along with a full Compression,+ Leak-down Tests would narrow down What you're looking for....

It could be as simple as Fuel Filters,.....
Or,...
It could be Much Worse....

Re: Merc 7.4 MPI splutters and excessive oil usage

I am starting to scratch my head now.... I did a total overhaul of the engine 2 years a go and it only has 70 hrs. Last season I fitted a new pair of stainless steel, one piece manifolds. The Oil usage has been there since the overhaul. Can it still be what you guys think it is ?

Thanks for all your replies

Jezz

Re: Merc 7.4 MPI splutters and excessive oil usage

Thanks Bubba, I will start with a compression test and take it from there.

Kind Regards
Jezzb

Re: Merc 7.4 MPI splutters and excessive oil usage

2 questions....

First what color is the smoke on start up.... Is it white, black, blueish/grey??

Second.... what brand and weight oil are you running in this motor?

Re: Merc 7.4 MPI splutters and excessive oil usage

jezzb said:

One more problem I have - which came up after I took the boat out of the water for the winter (no winterising done as I start the engine every 3 to 4 weeks),
Thanks - Jezz

Click to expand...

Where do you live does it get down to freezing? If so, just starting it every couple of weeks wont solve the problems that winterizing does...