5.0/305 Mercruiser Problem

macgregora2769

Recruit
Joined
Jul 18, 2017
Messages
4
Hello,
Need some help, we just bought a 1980's Century 2000 Sport LX with a 305 Mercruiser and alpha outboard. I have had this boat out 3 times and had problems every time in the 3 months that we have had it. The problem seems to be electrical or fuel related. I can get the boat running in my driveway and it seems to run fine until I put it in the water. I have take apart carb and cleaned it out and found the fuel filter on the carb to be completely clogged. Cleaned that out and the boat ran much better. Took it out on the water launched it and let it warm up. Went to put it in reverse and it stalls. Let it warm up more and I was able to get it in gear and out without issues. Started out of channel to the lake and as I am trolling it is spitting and sputtering but I noticed that if I hold the ACC switch then the spitting and sputtering goes away. But this issue only seems to be at low RPMS as when I got out into the lake I put in full power and the boat seems to run fine. Before it would fall flat on its face. So as I was coming back into the channel the boat out of no where stalled on me and will not start back up. We have spark tested the plugs they seem to be fine unless its an intermittent issue. I ohmed out the coil its within ranges. The cap and rotor are new. The only thing I can think of is maybe ignition system but any input would be appreciated please help!!!
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
52,227
welcome aboard

first, with any new to you boat, you really need to go thru and perform every bit of maintenance

pull the drive, replace the raw water pump
inspect the bellows and u-joints
grease the splines
align the drive
change the bellows
adjust the lower shift cable (replace as required)
change the gear oil
change all filters
pull tank cover and inspect
change engine oil
change plugs, cap, rotor, wires

and with your 1980, change the points and adjust dwell and timing.

your tank has crud in it, hence the plugged fuel filter. I would also suggest installing an in-line fuel/water separator filter
your lower shift cable is at least, out of adjustment. most likely you need to replace
if you haven't addressed your points yet, now is the time to do so. at a minimum, file the points and set gap and dwell and timing. or replace the points, file, them, set the gap and dwell and timing.

I will re-iterate above. you bought a used boat with an unknown maintenance history. time to do ALL the maintenance
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
19,023
:welcome:

. . . to iBoats.

When you say " hold the ACC switch" do you mean the ignition switch (key) ? If so, check the wiring behind the switch for any loose connections, or even replace the switch.
 

wahlejim

Master Chief Petty Officer
Joined
Jul 23, 2015
Messages
884
Need more information that "1980s". The 80s is when they were switching over ignition systems. I have a 305 from 85 without points. My boat is a 1980 and the original engine had points.

I am leaning more towards crud in fuel. System needs to be cleaned and exterior canister type fuel/water separator should be installed.
 

macgregora2769

Recruit
Joined
Jul 18, 2017
Messages
4
Thanks for getting back to me guys. There is a fuel water separator on my boat. It is a 1982 and I believe it is the original motor. I bought this boat used from a very well known local marina and they had told me all the stuff that they had done to it which one of the items was I was told they replaced the cap and rotor. I did more working to it today checked the plugs and they carb filter again. Everything seems to be fine. I was watching what appears to be the fresh fuel I put in coming out of the jets and into the carb. But I still had no luck getting this boat to fire. Its turning over strong, but will not fire. I looked more into the ignition/ ACC switch situation that I have going on right now and they have the wires coming right out of the turn key ignition and right over to the ACC switch and then back to the engine. That seems a little weird to me. Why wouldn't it be wired straight from the ignition to the starter. What are your guys thoughts on that? As far as loose wires in the back of the panel I was going through that today as well and took care of all of that. No problems there anymore. Still no luck. I thought that there was a lot of **** in the fuel tank as well but now that I cleaned the carb and I am getting fresh fuel in the carb and the fuel water separator I was told was new, so it doesn't seem to be a fuel issue but I could be wrong. Scott, as far as all of the routine maintenance that you are talking about, the friend of mine that helped me get this boat used to be the manager at the marina and worked the deal for me with the owner and he was told that the majority of this stuff had been done the oils look good the bellows look fairly new no rips or tears, I could probably figure out how to get to the tank and inspect that but as far as I know most of it seems to be done. Thanks again for the help guys and please keep the help coming. I am on the verge of taking this thing back to the marina and demanding money back or that they fix it but with wife out on maternity leave its not the preferred option to spend a whole lot right now. I might just get rid of it and buy a way newer one next year. FYI the only reason I bought such an old boat is because I wanted to make sure the family was going to enjoy it before spending more money on one. So the best option is to get this one running for this year at least. Thanks again .
 

khe

Petty Officer 1st Class
Joined
Dec 7, 2012
Messages
234
If the inline filter on the carb. was full of crud, my guess is the external fuel water separator is full of crud also. Take it off and dump the fuel into a clear container and see if there is a bunch of crud that comes out. If there is, replace the filter.

Have you checked for spark?
 

macgregora2769

Recruit
Joined
Jul 18, 2017
Messages
4
I had it running again and since it died again last Saturday I have not spark tested it yet but we have spark tested it previously and it was firing which leads me to believe it might be an intermittent issue I am currently running through the whole thing agaim
 

khe

Petty Officer 1st Class
Joined
Dec 7, 2012
Messages
234
If it dies and then won't re-start, that's when you need to check for spark.

When were the points and condenser last replaced? Have you checked the condition of the points?
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
43,848
As khe mentioned, take the fuel filter off and dump it into a baggie or something clear. They might have said they changed it but verify it was done and also that you have clean gas. Smell it to see if it smells like gas or something else with it
 
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