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Fuel problemmaybe

D

dale Clark

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"I have a 87 mariner 135 that

"I have a 87 mariner 135 that will idle and rev fine in back yard with ears, once in lake and in gear it dies. Ok, fuel problem, maybe, I have replace fuel lines (three times) cleaned & checked tanks, replaced fuel pump and checked twice,removed 3 carbs, adjusted floats and cleaned. Still will not run in gear? Now I am not only ugly, I feel stupid, any suggestions or do I start over again. Its a long way to lake to check results every time, Thanks"
 
Trouble shooting starts with a

Trouble shooting starts with a compression check----always-----NEXT is a spark check to make sure that each plug gets enuff to jump a gap of 7/16"-----there is no point starting anywhere else.
 
"Thanks, I started everything

"Thanks, I started everything when I got the motor last year, and checked again this year, compression is very good and constant in all 6 cyls, linkage and sync is right, spark is very good, not positive about timing, but it revs well when not under load."
 
What happens in the lake? It d

What happens in the lake? It dies or will not go over 2000RPM? (plows) You are setting the carbs in the lake right? If you set them on land you be way off to the rich side without the exhaust muffed.
 
"Hi 'Bandit, Sorry for jum

"Hi 'Bandit, Sorry for jumping in here as I have no advice for Dale,I'm curious, you say if the carbs are set on land they will be wrong for the lake,would this apply to my beautiful
lol.gif
800merc/1969 at sea level,I set the carbs in the backyard(tried)?"
 
"The final adjustment is done

"The final adjustment is done on the water. Maybe not in '69, but by '87 they were becoming finely tuned."
 
"Thanks Bandit,Will try anythi

"Thanks Bandit,Will try anything at this stage to get this merc up to rec. rpms,too many euro/$'s laid out to burn it at this stage"
 
"Well, you have not done all t

"Well, you have not done all the spark checks in this engine yet. There is more that can cause problems. The part about the timing needs to be done. The stator/switchbox could easily be bad. Or the idle stablizer. "
 
"I have not checked the timing

"I have not checked the timing as I said, nor much of the ignition part. I am getting good spark and I was pretty sure it is or was a fuel problem. The carbs do not have any adjustments other than changing jets for altitude, other than that the only adjustments are on the floats ( 1/16"). It wants to get to a higher rpm but then dies down, if I choke it it tries to pick up. Thanks for the suggestions, I will take them all and do them one by one till I get it right.Please keep them coming."
 
"What about the fuel pump? Do

"What about the fuel pump? Do that, too. They have a lot of problems with check valves on older motors's that were black rubber. Updated ones are clear plastic."
 
"When I first tried the motor

"When I first tried the motor on the lake, I started it, let it warm up, and made sure it was peeing, I revved it up and all seemed ok. When I put it in gear it would try to go then back down or die. If I kept choking it it would try to pick up. I switched tanks,put new fuel lines and bulb on and no difference. I got new fuel pump and another new fuel lines. I diconected at each carb while idleing to check flow and all 3 carbs get good gas flow. I am going t play with it again today, I thank you all.
"
 
"Hi
i am having the same pro

"Hi
i am having the same problem, but when i have my boat in the lake it runs fine until i put it in gear and then fule starts to poor out of the overflow on the side of the carb. It will not get above about 2000 RPMS.I am putting the Tach in today I have taken the carbs completly apart and cleaned the all out but i am going to look at the manual today about ajusting the floats. i will keep you all posted as how it goes and if anyone has any suggestion please let me know .
thanks John"
 
If it runs " fine " un

If it runs " fine " untill you put it in gear means that it is not producing the power it needs to turn the prop ( load )---- Check to make sure that you have spark at each cylinder ---check compression---The fuel leak indicates that float valve is defective or there is dirt affecting operation of the float valve.
 
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