175 dies when placed in FWD

[Tomstriton19]

Serial# 0G802859
Model# 1175412VD
MERCURY 175 L
Manufactured: 5/29/98
My engine started to malfunction on me about three weeks ago on the water. It would start up fine then when put it in FWD gear it would die. So two Saturdays go I installed new spark plugs, set timing, set carbs to factory setting of 1 1/4. I tuned this engine to a complete new beat, she needed It bad. took her to the water and tested I. I was able to get FWD idle into the 700-800 rpm range and running very smoothly. at this point the boat runs awesome. I go out this Saturday that just happened and she turns on just fine and takes the first run great. fish for about 2 hours and go to move, cranks up great. Go to put the boat in FWD gear and she dies, im stuck again. Im not sure what the problem is but this engine does not like fwd gear or reverse and I cant not figure out why. is it a lower unit problem?Any help would be awesome!
Tom

[moetorola]

Does it only seem to happen after making a run and then fishing awhile?

[Tomstriton19]

Yes, in the mornings it will start right up and run fine.

[Tomstriton19]

it will turn on just fine after a long run or fishing for awhile. but as soon as you put it in fwd it dies.

[tj]

.

[Tomstriton19]

I can get it to take off if I press the gas and shift at the same time and it will run fine but if not then it dies

[tj]

.

[moetorola]

My engine does the same after fishing awhile. I have to let it idle in neutral a little bit before giving it the gas.

My theory is that the carbs are soaking up the heat and the fuel is evaporating into intake, being the fuel is still under pressure. As the fuel evaporates the float drops allowing some fuel in, and the process continues.

Basically after fishing awhile the engine is in a flooded condition. Do not push the key in, it will make it worse flooding even more.

Things I did to help. But not completely fix.
Rebuilt the carbs, and installed new OEM merc needle valves and seats. And I pump the pump bulb before starting before every start especially after fishing awhile.

I chalk it up to todays fuels.

One other thing you could check, make sure the idle air valve on the head is not plugged. It opens at about 100degrees while engine is running you should feel a slight bit of suction and RPMs will drop a little when you put your finger on the open end of the valve.

My engine does not have an issue as bad in cooler temps or below. Only seems to have it really bad during summer.

[EuropeanAM]

Serial# 0G802859
Model# 1175412VD
MERCURY 175 L
Manufactured: 5/29/98
My engine started to malfunction on me about three weeks ago on the water. It would start up fine then when put it in FWD gear it would die. So two Saturdays go I installed new spark plugs, set timing, set carbs to factory setting of 1 1/4. I tuned this engine to a complete new beat, she needed It bad. took her to the water and tested I. I was able to get FWD idle into the 700-800 rpm range and running very smoothly. at this point the boat runs awesome. I go out this Saturday that just happened and she turns on just fine and takes the first run great. fish for about 2 hours and go to move, cranks up great. Go to put the boat in FWD gear and she dies, im stuck again. Im not sure what the problem is but this engine does not like fwd gear or reverse and I cant not figure out why. is it a lower unit problem?Any help would be awesome!
Tom

Tom:

Couple suggestions:

1. Open idle-air screws 1/8 - 1/4 turn COUNTERCLOCKWISE beyond where you are at. Helps compensate for today's fuel burn-rates.

2. Make sure engine is LEVEL TRIM, primer bulb pumped FIRM before EVERY engine start.

Hope this helps!