350Mag issue poss timing?

[toger13]

i have a 350 mag mpi 1998 modle with bravo 1 leg

it starts and idles fine and if you rev it nice and slowly its fine but if you bang the throttle down in netral or in gear it just bogs down and cuts out then to start it you have to hold the throttle at WOTand it turns over for a few seconds then you have to back it off quick and let it settle to idle again

fitted some new plugs today the old ones were very sooted up and the gaps were off large

i havent gone any further in to it checking the dizzy cap etc yet but was thinking the timing could be out?

what should the timing be as i dont have a manual i do have a strobe though lol

also it doesnt seam to get very warm none of the pipes get warm etc. i checked the stat also today which functions fine begins to open at about 160*

what are your thoughts

Thanks
Si

 

[Don S]

Re: 350Mag issue poss timing?

While you may have a 98 boat, are you absolutely sure you have a 98 engine? Unless you have checked into it you may not have, and it's very common. Engine model years and boat model years are different.
You are also right at a changeover year for the OEM manuals.
Do you have a Mercruiser SN handy for your engine?

 

[toger13]

Re: 350Mag issue poss timing?

hi sorry for the slow reply been out in the boat this weekend given it a good blast to see if it would clear it out as previous owner had just used it on a river for last two years so thought it might be chocked up but its still the same if you put the power down if cuts out and black smoke kicks back out of the flame arrestor

i have changed the plugs which were very sooted up changes the dissy cap and rotor arm which was knackard still the same i havent changed the leads or the fuel filter as they wernt in stock

i have also find it wont reach any where near max rpm @ WOT

it will do 3000rpm @ 39-40 MPH

it has the prop on that it came from the factory which is in good condition 19" pitch

serial number is 0L050645

it apears to be the earliest one in the 1998-2001 online manual it seams to have the wire to earth out on the data link connector to put it in service mode

Thanks
Si

 

[Don S]

Re: 350Mag issue poss timing?

You do have a 1998 engine. Go up to the Adults Only sticky at the top of the forum and download the OEM service manual for your engine. #24 is the one you want.
You might want to consider a Rinda scan tool if you don't have any type scan tool to read codes and outputs.
http://www.rinda.com/marine/mtspec.htm

 

[krisnowicki]

Re: 350Mag issue poss timing?

your tach is way off or speedo or both is way off. If you are doing 40 mph at very minimal slip you are doing 3700 ish rpms... check out this website ...
http://www.rbbi.com/folders/prop/propcalc.htm

 

[toger13]

Re: 350Mag issue poss timing?

them code readers arnt cheap are they

do these engines have and electronic rpm limiter like a efi car engine?

if so i can give it a quick blip to see what the rev counter reads the speed was off my gps unit so i would expect that to be correct?

Thanks
Si