Hello all - a very interesting and helpful discussion.
I had a 1993, 36' Nauticat with a 90 HP, 4 cylinder Lehman diesel. I installed a 12v electric fuel pump to take the place of the mechanical one. My mechanic also wired up the 12v fuel pump in sync with the oil pressure sensor so that if the engine lost oil pressure then the fuel pump would automatically shut off - thus adding further protection to the engine.
I owned the boat for 7 years with this setup and sold it 3 years ago to a friend. Over the past 10 years it has traveled thousands of miles and is still using the same electric pump that I installed in 2010.
Cheers!
Wally
Hi Cigatoo;
I never had a problem starting the engine with the oil pressure switch in the 12v fuel pump circuit. The engine always started quickly - even in colder weather and the oil pressure gauge would "jump" up into its normal pressure range in just a few seconds after I started the engine. So if there were a few seconds when the fuel pump was not running, it did not make any difference to the engine starting.
I also had a power supply bypass switch at the fuel pump that I could use to run the fuel pump manually - with or without the engine running. That proved to be a great setup when I was changing fuel filters and bleeding air out of the system.
Cheers!
Wally
Or 3/8ths of 5/8ths of fu^*all,as we say here.Not very much...
Any 12v fuel pump that's rated for diesel and has a flow rate of double your max usage will work fine. I have a 12v pump on all my diesels for filter changes and bleeding. Each will run an engine on its own. I buy the pumps on eBay, usually for less than $20 and haven't had one fail yet. They're cheap enough, buy two. Then you have a spare.
I have installed "FACET" brand electric fuel pumps on my Lehmans and they work well. This company makes a model with an all plastic body whick I chose just to avoid the surface rust that you get from salt air on the steel models. I made some blanks out of 1/4" aluminium to cover the holes where the original pumps were bolted to the block and I carry a 3rd pump as a spare, they are mounted in the fuel line between the filters and the motor and are very accessible and easily changed and as mentioned earlier , make bleeding a very simple exercise
Connecting the pump to the oil pressure switch sounds like a great idea..... However that tells me that the fuel pump wouldn’t kick on until the engine built up oil pressure. That would make for a long cranking period before the engine started. Was that the case or am I missing something?
...I've looked at the scores & scores of these pumps on ebay but they don't give me the lift specs. I don't need much , less than 18" for sure, but if it's a gravity fed pump it wouldn't do me any good at all. It's possible I would use it as an emergency get home pump too but normally it would only be used less than 10 minutes a year, which is why the cheap ones appeal to me.
Detroits return far more than they burn because the fuel lubes and cools the injector pump. Detroits are actually a pretty good fuel polishing system. Lehmans on to other hand return very little. So if a mechanic or fuel polisher tells you that all diesels return lots of fuel, look for a different mechanic or polisher.