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1995, 115 HP questions

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odellmac

New member
I know the 2 x 2 usually has a rough idle, but I can't bring the rpm down to the level it should be to not eventually damage the dog gear when I put it in gear. I have to keep it around 900 to 1000 rpm to keep it from dying. Carbs have been rebuilt in the shop, (supposedly). Things that have been replaced in the last 3 years, stator, trigger, all coils, plugs, and switch or power pack. I adjust the idle mixture screws from 1 1/2 to 2 turns for the best I can get it to idle. Any suggestions?
 
Nothing wrong with compression.----Flywheel key checked ?---Spark jumps a gap of 3/8" on all leads ?----New water pump impeller every 5 years ?
 
What is your idle timing set at? I had twin 1995 115 2+2 's and became very familiar with them. They idle very well when set up correctly. Out of the water, on a flush muff they would idle at about 1050-1100 rpm. In the water with back pressure 850 in neutral and 675 in gear, smooth as silk. 4 things to check: Idle timing at 0 to 2 deg ATDC, Throttle cam to roller gap at .030"-.040", top two carbs set slightly rich at about 1 /3/4" turns from stop. Make sure the accelerator pump diaphragm is not leaking. That's where I would start. The link and sync proceedure is very speciifc. Unfortunatley, I gave my factory manuals away to the fellow I sold the boat to but you should be able to find it online.
 
racerone said:
Nothing wrong with compression.----Flywheel key checked ?---Spark jumps a gap of 3/8" on all leads ?----New water pump impeller every 5 years ?
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Flywheel key is fine. I'll have to check the spark gap, I haven't done that. The impeller is due. Thank you.
 
fitz73222 said:
What is your idle timing set at? I had twin 1995 115 2+2 's and became very familiar with them. They idle very well when set up correctly. Out of the water, on a flush muff they would idle at about 1050-1100 rpm. In the water with back pressure 850 in neutral and 675 in gear, smooth as silk. 4 things to check: Idle timing at 0 to 2 deg ATDC, Throttle cam to roller gap at .030"-.040", top two carbs set slightly rich at about 1 /3/4" turns from stop. Make sure the accelerator pump diaphragm is not leaking. That's where I would start. The link and sync proceedure is very speciifc. Unfortunatley, I gave my factory manuals away to the fellow I sold the boat to but you should be able to find it online.
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I have a manual coming in the mail. I'll check the timing and gap, the idle screws on the top 2 carbs are at 1 1/4 now, and there are no visible leaks. Thank you.
 
The idle RPM is set by the spark advance for 675 +/- 50 in the water in F gear, boat moving. Carbs start off at 1 1/2 open from a "soft" closure....soft closure means that you didn't torque the screws down and score the needle point with a groove that makes correct adjustment impossible.
On the water with trim mid position, firewall the throttle. If it balks, back off a screwdriver width on the carb screws until it will take throttle and come up on plane.

One has to assume that your prop is pitched for your selected boat and normal load. Too much pitch will prevent a satisfactory adjustment.
 
Texasmark said:
The idle RPM is set by the spark advance for 675 +/- 50 in the water in F gear, boat moving. Carbs start off at 1 1/2 open from a "soft" closure....soft closure means that you didn't torque the screws down and score the needle point with a groove that makes correct adjustment impossible.
On the water with trim mid position, firewall the throttle. If it balks, back off a screwdriver width on the carb screws until it will take throttle and come up on plane.

One has to assume that your prop is pitched for your selected boat and normal load. Too much pitch will prevent a satisfactory adjustment.
Click to expand...
I tried adding this to the above post and the 5 minute time limit (why so short....I had to go pee) so here are a couple of additional comments:

I like to run premium gasoline/ethanol in my engines (currently a 115 2+2, 2002 edition) for better performance. 87 Octane is the "minimum" recommended fuel.....expect minimum performance with minimum fuel and my premium fuel gives me better results......I use Pennzoil Premium Plus from Walmart at 50:1 ratio which is a synthetic blend and run 1 oz of Sea Foam in addition to the above to keep my fuel system squeaky clean.

The other thing I like to do is when running at low speeds, trolling or what have you, I trim the rear of the engine up about 10* over vertical and notice an immediate smoothness in the performance. I got the idea from a Mercury commercial with their 20 hp fishing motor, way back in the 70-80 time frame best I can remember, that had a tilted drive train/powerhead by design. The advertisement said that having the cylinders tilted forward, prevented fuel from puddling back where you are expecting combustion and offered much smoother trolling performance. If Merc. designed a fishing motor based on that design approach, must be something to it.....and for "me", its especially true with the 2+2 running below the 1800 RPM kick in speed for the lower 2 cylinders.
 
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