Mercury 150 not performing well under load and drinking gas.

[karnage]

Think the rainbows will just be 2 stroke.
I think you really need to clean the carbs properly, to be honest. Spraying them rarely does the full job. Been fooled in thinking it does, far too many times before now. Learned to just do them properly and save the wonder or bother of taking them off again.
Is the fuel definitely good and fresh ? Any filters fresh too ?

Fuel should be fine, I mixed up some 50:1 with 87 yesterday. Filters, I don't even know which to check. I checked the cone fuel filter this morning and it looked pretty much new. No filter in the air cover on the carbs. As for the carbs, I guess I can take 'em all apart and go get some carb dip. Gonna wait until I check compression.

 

[karnage]

Think the rainbows will just be 2 stroke.
I think you really need to clean the carbs properly, to be honest. Spraying them rarely does the full job. Been fooled in thinking it does, far too many times before now. Learned to just do them properly and save the wonder or bother of taking them off again.
Is the fuel definitely good and fresh ? Any filters fresh too ?
I’d also try pumping the fuel primer bulb to see if it makes a difference to things. That may indicate the rough health of the fuel pump occasionally.
When the oil injection was done away with. Has it worked and performed since then ? If not, I’d look to see if you have any open ended oil fittings that are drawing air and not been dealt with accordingly.

I messed with the bulb a fair bit yesterday and when I went back to it had maybe 1/8 of it slack but its majority tight. The oil injection delete was done by the previous owner and he said he did it properly and it all ran right. Ill take a look though. Again, I only got the boat on plane on one trip since I bought it.

 

[jimmbo]

The nuts that hold the carbs on look like they have been wrenched on many times, so I suspect the High Fuel burn has been an ongoing issue for while.
As the powerhead has been changed, and apparently from a 200 to a 150, makes for some Questions.
Was the complete Powerhead swapped, carbs and all, including the Exhaust Tuner in the midsection?
If not, then having the carbs and/or the exhaust tuner from a 200 with a 150 powerhead can lead to less than Optimum Performance and Fuel Consumption.

 

[karnage]

The nuts that hold the carbs on look like they have been wrenched on many times, so I suspect the High Fuel burn has been an ongoing issue for while.
As the powerhead has been changed, and apparently from a 200 to a 150, makes for some Questions.
Was the complete Powerhead swapped, carbs and all, including the Exhaust Tuner in the midsection?
If not, then having the carbs and/or the exhaust tuner from a 200 with a 150 powerhead can lead to less than Optimum Performance and Fuel Consumption.

That's an interesting and valid observation, either way ill try to get it running under load. Today I went and got a compression test kit and tested all 6 cylinders and every cylinder had a max compression of almost exactly 100. I'm not sure what is optimal for this engine, but there doesn't appear to be a dead cylinder. I took the fuel pump apart mostly and put it back together, engine still idles fine, little filter is clean. I'm back to the carbs if its not timing related. I guess I should take them apart and inspect them again, more thoroughly clean them.

 

[Scott Danforth]

100 psi is low if your gauge is right

130 psi is normal

 

[Dukedog]

that looks like it was a complete drop on power head.. anything that old is gonna have some nicks n bruises... looks like a new stator and trigger?..
jus by tha way ya describe things you really need an OEM manual BEFORE ya start doin' things ya don't know anything about (no offense meant) to tha power head.. jmo.

go to tha link for your parts for it and tha manual part number..

1984 Outboard 150 [ELPTO] [1150724] - Parts Lookup | Crowley Marine

View parts diagrams and shop online for 1150724 : 1984 Outboard 150 [ELPTO]. Offering discount prices on OEM parts for over 50 years. FAST $4.95 shipping available.

www.crowleymarine.com

 

[Dukedog]

that looks like it was a complete drop on power head.. anything that old is gonna have some nicks n bruises... looks like a new stator and trigger?..
jus by tha way ya describe things you really need an OEM manual BEFORE ya start doin' things ya don't know anything about (no offense meant) to tha power head.. jmo.

go to tha link for your parts for it and tha manual part number..

1984 Outboard 150 [ELPTO] [1150724] - Parts Lookup | Crowley Marine

View parts diagrams and shop online for 1150724 : 1984 Outboard 150 [ELPTO]. Offering discount prices on OEM parts for over 50 years. FAST $4.95 shipping available.

www.crowleymarine.com

manual part #90-976583

 

[karnage]

that looks like it was a complete drop on power head.. anything that old is gonna have some nicks n bruises... looks like a new stator and trigger?..
jus by tha way ya describe things you really need an OEM manual BEFORE ya start doin' things ya don't know anything about (no offense meant) to tha power head.. jmo.

go to tha link for your parts for it and tha manual part number..

1984 Outboard 150 [ELPTO] [1150724] - Parts Lookup | Crowley Marine

View parts diagrams and shop online for 1150724 : 1984 Outboard 150 [ELPTO]. Offering discount prices on OEM parts for over 50 years. FAST $4.95 shipping available.

www.crowleymarine.com

manual part #90-976583

The previous owner put in a lot aftermarket parts including a new stator and trigger. A service manual would make my and this engines life a lot happier. The one over 100$ is my best bet huh?

 

[Dukedog]

yeah, i squealed like a pig under a gate first one i bought many (to many) years ago... it stings a little at first but tha OEM is well worth it.. tha other junk like a clymer is jus that, JUNK... jmo

 

[Chris1956]

The fuel pump is connected to the crankcase. As the pistons move up and down, pressure and vacuum from the crankcase is directed to the fuel pump diaghram, which causes it to move in/out. On the other side of the diaghram is the fuel, and some one way valves. As the diaghram moves, fuel is pumped to the carbs. If the diaghram leaks, raw fuel goes into the crankcase, can foul spark plugs and is definitely exhausted into the water as a rainbow.

I would expect you to have a square fuel pump, bolted to the block on the port side. Just because it doesn't leak externally, doesn't mean it doesn't leak into the crankcase. Rebuild kits are pretty cheep.

 

[Dukedog]

The fuel pump is connected to the crankcase. As the pistons move up and down, pressure and vacuum from the crankcase is directed to the fuel pump diaghram, which causes it to move in/out. On the other side of the diaghram is the fuel, and some one way valves. As the diaghram moves, fuel is pumped to the carbs. If the diaghram leaks, raw fuel goes into the crankcase, can foul spark plugs and is definitely exhausted into the water as a rainbow.

I would expect you to have a square fuel pump, bolted to the block on the port side. Just because it doesn't leak externally, doesn't mean it doesn't leak into the crankcase. Rebuild kits are pretty cheep.

Chris, his is tha old oblong style.. mounts on tha reed plate on other side..

 

[karnage]

Chris, his is tha old oblong style.. mounts on tha reed plate on other side..

The explanation of the function of the diaphragm was helpful. It is a more oblong shape right beside the carbs. I did disassemble and reassemble this yesterday. Replacing most of the assembly with this kit is on my list of things to try (https://www.crowleymarine.com/parts/3699.cfm). Work is slowing down my progress on this project but recleaning the carbs is my current task. I'm stubborn and if I don't visually see something as broken It's hard for me to want to replace it, but I get these things need precise operation. Thank you guys much for the input.

 

[karnage]

Big day in progress for the motor. I cleaned out the carbs again this morning, used a wire, air, and carb cleaner. I replaced the primer bulb, come to find out wasn't really necessary but it doesn't hurt to have a new one. And I adjusted the floats on the carbs a hair. I noticed they were all level with the flange or gasket on the bowl, opposed to the bowl without the gasket so I tinkered with that just to see what effect it had. With the adjustments done I took it out to the lake. Started it up, idled fine, put it in gear and got away from the ramp. I gave it gas annddd same old bog. I cranked it up a few more times, idled, kept trying and I got it to the floor at 2000 rpms riding around. Restarted it, same thing, it wasn't bogging out. I'll save majority of the story here to say after I made that progress I noticed the top screw on the timing arm was loose. It only has one bolt and a rubber cap on the end. I loosened it 2 times and tried again and the rpms started climbing. My friend had to get to the front of the boat for it get up and start getting on plane, but it got there. I continued to mess with the top screw turning it quarter turns and on our last run we got onto plane without any moving around and distributing weight. We got up to 51 with the motor fully trimmed at around 5 5500 rpm I believe (I didn't look on the last run). And that's all she wrote for the gas today. So, cleaning the carbs helped but also a big deal was timing. Now, I outta ask what is expected from my motor given the circumstances. I'm happy with the performance, but what should I be expecting from my motor at 5000 rpm with a 23 pitch laser 2 prop fully trimmed? is 50mph healthy? Any concerns or comments you guys have for me?

 

[jimmbo]

You have to determine what gear ratio you have, before you or anyone can running the numbers as to what a 23" prop will do at 5000rpm, as at one time the motor was allegedly a 200, and 150 was placed on it. The two engines normally have different Gear Ratios. However, the Gearcase might not be the original 200 case...

You timing is likely messed up.
You said it looked like a complete powerhead swap, I still wonder if the Exhaust Tuner/Megaphone was also changed, as it will affect the engine Power/Torque Curves

 

[Scott Danforth]

You have to properly set timing before you worry about the prop.

 

[karnage]

You have to determine what gear ratio you have, before you or anyone can running the numbers as to what a 23" prop will do at 5000rpm, as at one time the motor was allegedly a 200, and 150 was placed on it. The two engines normally have different Gear Ratios. However, the Gearcase might not be the original 200 case...

You timing is likely messed up.
You said it looked like a complete powerhead swap, I still wonder if the Exhaust Tuner/Megaphone was also changed, as it will affect the engine Power/Torque Curves

Thank you

 

[karnage]

You have to properly set timing before you worry about the prop.

Any measure or way for me to get it correct? or should I continue to tinker with the screw until it gets on plane faster and runs more efficiently?
I'm sure the service manual would help me do this properly, but I haven't gotten one.

 

[Scott Danforth]

You wait for the manual

 

[jimmbo]

Any measure or way for me to get it correct? or should I continue to tinker with the screw until it gets on plane faster and runs more efficiently?
I'm sure the service manual would help me do this properly, but I haven't gotten one.

Tinkering can result in melted Pistons, broken Rings, etc.
Get the Manual, a genuine Factory Manual for that Powerhead.