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Mercury 40hp Boggs

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dalejam

New member
Hi everyone , I have a 1995 Mercury 40hp 4 cyl.
When I bought the boat had a bad power pack . Replaced it have spark on all 4 cyl. Took it out on my local lake idle is nice and low does 2 mph when in gear. After I try to get up on plane it bogged down then shut off. Have to wait a while then will start up. So I had already rebuilt carbs. So only thing I could think of was fuel pump. So orderd ciera kit . Installed and it didn’t bogg down it got up on plane boat does about 25 not a problem there. But it does not seem like it’s 100 percent . So I checked timing it is good . So I took a video of it . Hope it helps you so you can help me.
I have the manual for it . Not afraid to try things .
Thanks in advance Dale
I took a video but it does
Not allow
Me to upload it ??????

View attachment 30712
 
so my QUESTION IS
How do i adjust ? to get rid of the bog, it has 2 carburetors, they have adjustment screws in the front of them. they are turned out 2.5 turns out. someone wrote to me and told me they had the same issue, there fix is having the adjustment screws out 1.5 turns. can any one tell me if they had a similar issue and what was there fix .
Can someone tell me how to add a video so i can show the issue
 
Manual says 1.25 turns out to start, open them more if bogging. Have you checked the compression? Will the spark jump a 7/16 gap on all cylinders? 5000-5500rpm max. Sounds like its running on 3 cylinders
 
mgj4135 said:
Manual says 1.25 turns out to start, open them more if bogging. Have you checked the compression? Will the spark jump a 7/16 gap on all cylinders? 5000-5500rpm max. Sounds like its running on 3 cylinders
Click to expand...
Sorry time has gotten away from me . So I backed it out 1.25 turns out ran like a champ . Wow…..
Then the following weekend went out got up on plane and fell on its face . So I was confused . Got in and found one of the carbs had no effect if I coverd it . Other one would shut motor off . So I ran in drive way . Spark was on all four cyl but one cyl had very little effect . So I took out the volt meter and manual all were within spec . Checked everything according to the book when running too. All good so I took carbs off cleaned them out back on . Runs and idles smooth. I even followed the book on setting timing and adjusting the connection to the cab by the little y looking piece that opens the carbs. I also put ampiece
Of paper I front of carbs . To see if the reeds were bad . It sucked it inword not blowing it out.
So I think something got passed the filter or broke free in the line after filter . I am going to put another type of filter on.
It runs smooth in driveway now.
Hope to get out this weekend to see .
I will return with info
Thanks for the reply
 
Dale, have you done a compression check yet? I have the same motor, and had same kinda problems, did a comp test and had 119-114-120 and 60lbs. Completely destroyed cyl 4 all due to a lean condition. Hopefully you aren't having the same prob, but if u are the sooner you catch it the better. Good luck
 
Sorry been a little
Busy. Other things in life happened. I did dona
Compression test. I don’t remember the numbers but they were all very close in numbers. Good numbers. I will
Try to do a recheck this weekend and will post findings.
Thank you again . Sorry for being late to my own thread. Life !!!!!!
 
I don't think a compression problem is your trouble shooting catalog since it ran good once. Nor do I think spark is your problem. I think you need to clean up your fuel supply, what ever that entails and you will solve your problem.
 
Texasmark said:
I don't think a compression problem is your trouble shooting catalog since it ran good once. Nor do I think spark is your problem. I think you need to clean up your fuel supply, what ever that entails and you will solve your problem.
Click to expand...
I agree one hundreds percent. If it would not rain after work or on weekends I could test the damn boat motor. Was thinking of leaving it on trailer and just putting it in lake and run it in trailer.
Any thoughts ????
 
Wouldn't hurt then if its running good back it off and take it for a spin. If you had the same problem as billybl you wouldn't have had that good run.
 
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