Terrible Off Idle Bog Merc 1500

[macx]

Title says it. Relatively low hours 1976 motor,<br />not used very often. Sat for couple years, then problem surfaced when tried to run it. Went thru carbs and cleaned with carb spray and compressed air, checked compression - good, new fuel pump diaphram. No improvement.<br /><br />Another question - don't think it made the big change with the bog, but noticed the timing belt is looser than it maybe should be. What's the timing on these?<br /><br />Thanks for any info!

 

[Clams Canino]

Re: Terrible Off Idle Bog Merc 1500

Is it still propped the same?<br /><br />Barring that, try opening up the idle needles 1/4 turn each.<br /><br />Max advance on the timing is 21 degress BTDC.<br /><br />-W (taking a moment off from hell)

 

[macx]

Re: Terrible Off Idle Bog Merc 1500

Thanks for the info on the timing!<br /><br />As for the bog, yes it's still the same<br />old slightly beat up prop.<br /><br />Everything was the same from when it ran<br />fine till when the bog started just after<br />the motor had not been run for a couple years.<br />The new fuel pump diaphram, and disassembling<br />and cleaning the carbs (and the compression checked well within specs) didn't help a bit or<br />change how it acted at all.<br /><br />It's probably in the carbs - maybe didn't<br />get all the passages cleaned after sitting<br />and getting gummed up from old gas?<br /><br />Starts and idles just fine, but any increase<br />in throttle at all, no matter how slowly,<br />and it mostly just dies. Once in awhile<br />it will catch and rev up if I "pump the throttle", then runs fine and pulls good <br />once it gets beyond the off-idle bog.

 

[bubbakat]

Re: Terrible Off Idle Bog Merc 1500

Change those spark plugs and see if that will help

 

[corm]

Re: Terrible Off Idle Bog Merc 1500

I run my needle valves 2 turns open.

 

[2cycle]

Re: Terrible Off Idle Bog Merc 1500

As mentioned in other posts, I would definitely suggest opening the idle speed adjustment needles. I have a 74 150 and when I took it out for the first time it would die every time going into FWD or reverse and attempting to accelerate. This is not as noticeable running on a garden hose, but I had to open my needles up to about 2 1/4 turns before the engine would accelerate without bogging.