Mercury 1150 fuel pump question

[Kailofsouls]

I've got an older 72-73 merc 1150 and I need to replace the fuel pumps (older style triangle shape) I can't get to the lower one it's below the level of the lower cowl is there a trick to getting to it without pulling the power head? I can't figure out how to get the lower cowl off otherwise.

 

[racerone]

Well----I do not think you would have to pull the powerhead to remove a fuel pump !-----Buy or make the tools to reach the screws.----Repair kits are available for these pumps.-

 

[Chris1956]

Remove the 4 rear cowling support bolts as well as the 2 front ones. The lower cowling should droop enough to get to the fuel pumps. If not, remove the 4 sheet metal screws on the very lowest part of the lower cowl. Where it says "115 HP". When that U shaped piece of metal is removed, the lower cowling will have more room to move.

 

[Kailofsouls]

Ok I'll try that thanks didn't even see the bolts first time.. all I found was unbolting the front and back vertical plates let it wiggle around a bit.

 

[Kailofsouls]

On a side note does anyone know what the cold crank compression should be?

 

[Chris1956]

The compression should be even (or within 15%) on all cylinders. No exact spec is cited.

 

[Kailofsouls]

Ok thanks! Thanks to Ebay and Amazon I can use all this down time to get my boat set for summer lol

 

[Faztbullet]

If its a 72-73 it will have hi dome pistons unless it was rebuilt and compression will should be 130+psi. Any lower than 120 and motor has some wear or low domes. There is a lead seal on wire in a bolt in middle of crankcase and if still intact it has not been rebuilt.

 

[Kailofsouls]

Is the high dome pistons why it has those electrodless spark plugs? Those plugs can be a pain to find around here. Replaced them last year. 4 part stores to buy 6 plugs of the same brand lol. Then I learned how to make my own spark plug wires this motor still had the original wires on it. Needless to say the shielding was a bit cracked on them

 

[jimmbo]

No. There was no difference in the type of Spark Plug used in the High Dome(pre 1984) and the low Dome(post 1983) Pistons.

 

[Chris1956]

Did you use solid stranded stainless steel core spark plug wires? That was original equipment.

Also, the gapless spark plugs were used on virtually every Mercury outboard for 25 years. They should be pretty easy to find, I would think.

 

[Kailofsouls]

The spark plug wire I bought was made by serria. it was solid and silver in color but I can't remember what it was titled. I do know the only premade wires I could find were $150 for a set. Making my own cost less than $50. Plus the fancy wire stripper/crimper. Not the first time I made wire for this motor. the main wire harness was rotted, and a replacement is very expensive. so I got different colors of spooled wire built my own with the original plug.

 

[Chris1956]

Solid conductor for the spark plug wires, right? Resistance should be futile (actually zero).

You used to be able to buy spark plug wires for that motor for $6 each. They came with the screw terminals crimped on. You cut them to size and installed the spring ends and boots.

The official name for them was yellow tiger tails.

 

[Kailofsouls]

I believe I saw them as well but making my own was a lot cheaper and really easy. Just another crazy question. Is it possible to cut off the old fuel line rubber and replace it on the fittings with hose clamps? The rubber is looking rough and starting to crack. Just some fyi when I bought this boat first summer I had it with a beat up prop I was getting 30-35 mph on a 17 foot tri-hull. The next year and ever since (3 years now) I can't even get it to plane out.. cleaned carbs several times, linked and synked it, replaced timing belt (was cracked) rebuilt all the wiring harness, gas is mid-grade 50:1 mix, and new prop same pitch as the old one. I even bought a timing light and checked that. Plugs all look normal, and it starts and idles great 550-600 rpm by an aftermarket tack. But it won't hole shot either bogs out or stalls, and rpms build with gentle acceleration but bogs out then climbs/bogs again. I've got fuel pumps and carb rebuild kits on the way when they get here I'm going to recheck compression as well.

 

[Chris1956]

If I remember correctly, the fuel line connections between the old triangle style fuel pumps had brass screw ends. However, I am not sure if the rubber parts are replaceable. You might look on the crowleymarine web site and see what they say.

It is likely a hardware store will sell brass thread to hose barb fittings that fit, but I have never tried it.

Bogging on acceleration can easily be caused by carbs set too lean. It is very common on those motors, if you have adjusted them for smooth idle. They have no accelerator pumps, so the idle mixtures need to be much richer to compensate.

You might try opening the idle mixture screws 1/8 turn and retest acceleration. Open them one at a time (top carb then mid carb and then bottom carb) and test acceleration after each adjustment.]
usually the top carb needs to be a bit richer than the mid carb. Usually the bottom carb is the leanest.;

 

[Kailofsouls]

I thank you for information I'll try that when the temperature finally goes up.. soon as my carb kits and fuel pumps came in it gets cold and snowy. Go figure right? LoL

 

[Kailofsouls]

Sorry for double post browser mucked up