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Merc 50 Sputters at mid throttle

T

tow_n_me

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"HI, I have a 95 mercruiser 5.

"HI, I have a 95 mercruiser 5.0 with a 2barrel Mercarb. It has New Thermostat housing, Exhaust manifolds, Plug wires, Spark plugs, Ignition Coil, Fully charged batteries. The Problem is it is hard to start With one battery on But when i switch too two batteries it will start up (barely). And when throttle up to plane and almost to full speed it will sputter and cut back bog out. So i read some threads on this forum and Drained the gas tank. Checked the gas vent hose and anti-syphon valve. Also i cleaned the fuel filter at carb. Check the spark plugs and they looked very carbon fouled especialy the #8 cylinder. I pulled the water fuel seperator and i couldnt see water in a glass jar but there were alot of little black specs. These specs were also in the filter at carb(just a few).
Could bad gas or watered gas cause carbon fouled plugs? Could just a few black specs in the fuel filter at carb cause the boat to sputter at high speed? I'm yet to take it out for a test run after the new gas and cleaning the filter but is there anything else i'm missing? Probally just the carb."
 
".."Probally just the carb

".."Probally just the carb."

Agreed. The accellerator pump isn't putting out a good enough shot. See if there's an ajustment for a greater shot and, if so, use that setting.


Jeff"
 
"Thanks for your reply Jeff. W

"Thanks for your reply Jeff. Well took it out and the sputtering stopped. Thank god it wasnt the carb.Although it could use a rebuild.I guess the black specks were coming from a bad fuel intake hose from the tank. But theres another problem. I think the sparkplugs are getting carbon coated. Shes runnin to rich i guess. Its hard to start up. But after running for awhile i'll turn the key off then i'll turn it right back on and it will fire right back up. But if i let it sit for more than 5 minutes I will have trouble starting it. Maybe idle and timing? could somone how to adjust this just right if this is the step i need to take? Oh, Also it will sometimes die when i go from forward or reverse to neutral i guess that would be a shift interupter adjustment? And jeff if thats your boat in That pic, You have a Niiiiice ride."
 
"You Need to Rebuild or Replac

"You Need to Rebuild or Replace the Carb......

No amount of Adjusting is going to Fix your Problem.......

The Carb is all ^ucked Up..........
Either Rebuild it, or Replace it.........."
 
"Ok, I'm gonna order a reb

"Ok, I'm gonna order a rebuild kit. But i already have a 3.0 rochester 2bbl thats new from my last boat. Would it be easier to swap the electric chokes between these carbs they look the same?"
 
"Took it out again today, Very

"Took it out again today, Very hard to start. And everytime i went from forward or reverse back to neutral BOOM dead. Checked the fuel filter and it had some more specks. So I'm on the prowl for a good mercarb rebuild kit. I kept thinking it was the shift interupter. Also, It has the origional fuel line from pump to carb and it looks rusty on the inside."
 
I think it might be the interr

I think it might be the interrupter switch. It would explain why also my boat was grinding into gear. I know shift cable adjustment play a roll in this but i guess there is not enough hesitation with the switch. But today i seen it was sticking alittle. I took it completly off. And no more hard starts even after it sits for awhile like before.
 
"JAY;
When it dies see if the

"JAY;
When it dies see if the interrupt switch roller is in it's V notch. If not, your cables need adjusting, or maybe your lower shift cable needs to be replaced.
The switch roller should be in the V notch at all times except for a small instant as you shift out of either forward or reverse.
You might want to try some 2-4-C lube on the cable sleeves.
Rod"
 
"BTW;
The interrupt switch ha

"BTW;
The interrupt switch has nothing to do with grinding into gear. This is caused by bad cable adjustment or a sticky lower shift cable.
You can try undoing the nut that fastens the eye end of the lower shift cable, and manually push the cable all the way in and then out. It should move easily without binding or sticking. Any tight spots or sticking means it needs replacing, or your upper shift shaft and slider assembly need to be greased.
Rod"
 
"Right on the money rod, All s

"Right on the money rod, All signs point to Lower shift cable. So today i pulled off the drive and it was coroded and right away i went a bought a shift cable kit. Thanks for all your comments guys."
 
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