PDA

View Full Version : mechanical fuel pump


drbesvold1
03-20-2008, 12:18 PM
does anyone have a pic of there mechanical fuel pump for the late 80's mc 190 , i just got my new one in the mail today and im confused on the proper way to put it in and would like to see a pic to get a idea of the correct way it goes in thanks

TMCNo1
03-20-2008, 01:51 PM
I've never replaced mine, but I would think, you would put the new one in just opposite of the way you took the bad one out.

Monte
03-20-2008, 02:03 PM
Can you repeat that? I didn't get it the first time.

TMCNo1
03-20-2008, 02:21 PM
That was funny, I posted it, edited it, it just sat there and never posted, went to pee and came back and the were 9 posts for each word that I had edited onto the original post. Thanks Cameron!

drbesvold1
03-20-2008, 02:32 PM
I've never replaced mine, but I would think, you would put the new one in just opposite of the way you took the bad one out. i have never had a mechanical i had a electric pump that the previous owner rigged up wasnt safe at all

JLeuck64
03-20-2008, 02:59 PM
Please post pics of your old pump and the new one for us. I'll try to sort it out for ya!

drbesvold1
03-20-2008, 03:13 PM
my old fuel pump

drbesvold1
03-20-2008, 03:19 PM
heres the new one

Prostar Rich
03-20-2008, 03:22 PM
Someone created a block off plate on the block where the fuel pump goes. Remove the two bolts on that plate and you will see there is only one way for the new pump to go on.

Prostar Rich

drbesvold1
03-20-2008, 03:29 PM
Someone created a block off plate on the block where the fuel pump goes. Remove the two bolts on that plate and you will see there is only one way for the new pump to go on.

Prostar Rich so rich are u saying that the long piece on the new pump goes inside the block

flipper
03-20-2008, 03:31 PM
yes, the long peice will be inside the block

drbesvold1
03-20-2008, 03:34 PM
yes, the long peice will be inside the block does it go in easy and i was reading in the indmar book that it goes right underneithe the cam shaft

JLeuck64
03-20-2008, 03:44 PM
Yikes! Looks like an aftermarket electric pump has been substituted for the original mechanical one. I am assuming your engine is still carbureted right?

OK, Your are going to need to remove whatever plate used to cap off the original pump mounting hole and clean up the old gasket material completely. Hopefully the bolts used for the block off plate will be long enough to use in your new pump, otherwise you may need to replace those as well. When installing the new pump pay attention how the pump lever arm fits against the eccentric that drives it. Use a flashlight to look down the hole to see the eccentric. Sometimes it is hard to bolt the pump down depending in which position the eccentric comes to rest in when the engine stops. If this is the case you can simply bump the engine over 1/2 to 1 revolution to move the eccentric a little bit. The new gasket should seal oil in the engine without any gasket sealer applied but go ahead and put a little on if you feel it's necessary. Don't know the tightening specs for the pump bolts but it just needs to be snug.

You will need to sort out which hose is for the INLET and which hose is for the OUTLET. These should be marked on the new pump, hopfully. If not you could either move the pump arm by hand while holding a finger over the fitting. The INLET fitting should feel like it is pulling a vacuum. You could also crank the engine over once the pump is installed and get the same results. The fuel line going to the carburetor should be hooked up to the outlet on the fuel pump. The fuel line coming from the fuel tank should be hooked up to the pump inlet.

Some marine fuel pumps I have seen will have a third fitting on them. That one is supposed to have a clear hose attached to the flame arrestor on the carb. In case the pump diaphragm ruptures it is safer to flood the carb and stall the engine than have all that raw fuel enter the crankcase and dilute the oil. POOF!!!

Good luck,
J

edit: dang, wish I had a faster connection speed! It always slows down when it start raining for some reason...

One last thought. I would assume the original inlet fuel line to the carburetor was actually steel tubing and not rubber. If so, your new pump will have a different style of connection than that electric fuel pump. It may look like it has female threads to which the male end of a fitting would screw into. If that's the case and there is nothing of the original inlet fuel line remaining, you will need to make a new inlet fuel line. That would require knowing what size fitting goes in the pump and what size fitting is in the carburetor. You would need to purchase several feet of the correct diameter of steel tubing (sorry, can't remember) and a tubing bender and a flare tool. Using the flare tool requires some practice to get it right so seek out some help on that if you are unsure.

Don't forget to remove all of the afta market pump wiring...

flipper
03-20-2008, 03:45 PM
should, may have to wiggle a little bit.

denverd1
03-20-2008, 03:47 PM
it may not go in easy, depending on where the cam is in its rotation. Haven't put mine back on yet, but if it doesn't go in easy, a gentle push up on the pump s\hould be enought to get the bolts started.

Prostar Rich
03-20-2008, 03:53 PM
OK, Your are going to need to remove whatever plate used to cap off the original pump mounting hole and clean up the old gasket material completely. Hopefully the bolts used for the block off plate will be long enough to use in your new pump, otherwise you may need to replace those as well.



By the looks of those bolts in the picture they will not be long enough to mount the fuel pump. You will need to add new bolts to the parts list.

Prostar Rich

JimN
03-20-2008, 03:53 PM
The electric pump was not original and the connections are iffy, at best. Sure, most boat makers use them but that doesn't mean they're the right way to go.

Put some oil on the lever before you install it and if you have a mirror and flashlight, look into the hole to see if the cam lobe is down or if there's enough room to slide the new pump in. Also, you'll need a gasket, if the new pump didn't come with one. DO NOT install it with no gasket- you'll leak oil all over the bilge.

When you remove the old pump, use a brass barb fitting and hose clamps or better yet, replace the whole section of fuel line. In-line fittings don't do anything to help when you have a mechanical fuel pump.

stuartmcnair
03-20-2008, 05:41 PM
I just made a new fuel line so here goes from memory

Fuel line from the fuel pump to the Carb

3/8 line
1/4" pipe thread inlet at the fuel pump.
7/8" -20 is the connection for the carb inlet

You should be able to get the inlets from skidim and the line and bender from an auto parts store

I went with braided stainless and AN fittings which gives a better connection but it jumps the cost to about $75. If you want to do that PM me and I can give you a good deal on some leftover parts and the JEGS part numbers for the rest of what you need.

drbesvold1
03-20-2008, 09:45 PM
Thanks For All The Help Guys Ill Be Copying All Of This And Takin It With Me When I Start This Project After The Boat Comes Out Of The Paint Shop