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mechanic in the hamilton, ontario area?? '83 merc 80 help

C

cadormat

Member
Hi all, I was wondering if there's any members on here that are/ or know a mercury outboard mechanic that lives in the Hamilton area?

I've been having some issues with this motor since last year in a couple different areas and I think it's time that I finally bite the bullet and employ the hands of an expert. I'm about 99% positive that all it needs now is to be tuned. I've got it very close (I think) but from here it's a little out of my league.

Details:
1983 Mercury Thunderbolt 80hp
-Ran perfect when purchased beginning of last year, started acting up near the end of the season. No work done last year but fully winterized before being stored.
-New gas w/ ethanol treatment put in at beginning of this season
-Rebuilt both carbs and fuel pump including all new fuel lines
-new tank lines, bulb, connectors

I've got it to this point:
-Cold start: Prime bulb, crank w/ choke, fires and stalls, then crank w/ no choke, fires up
-Warm start: Starts immediately. Within two/three cranks
-Shift into gear: Shift into gear, motor stalls. Shift and give just enough throttle until throttle cable starts to move, motor sounds perfect and runs.
-Accelerating: In gear motor putts along great, 1/4 way through throttle range, motor has an instant of power loss then recovers and runs smooth and constant all the way through top end.

The only time it seems that I need to use the fast idle is after it stalls when shifting into gear and I try restarting it.
More details can be given as to what I've adjusted but it would take forever to type.

So is there anyone that could help me out? I'm hoping to get someone out on the water for a little troubleshooting. Hamilton Harbour.
By the way, I'm not a cheapskate. YOU WILL BE PAID!

P.s. Just incase assumptions are made, I do not have a tach on it for rpm reference.

Thanks guys.
 
I used to work in the Hamilton area-----------------Report your compression test results !!! -----Then we can go from there and maybe , maybe set something up.
 
What do your plugs look like after running at idle, but not in gear. Run for 5 mins, and look at the back of motor. Look for any fuel on water.
Then pull plugs, then let me know what you see

Steve
 
I played with the idle adjustment quite a bit and in idle I would get it to the lowest rpm with an even tone that I could (was revving high I think). As soon as I try to richen it even 1/8th turn, you can hear the rpm start to go up and down like it's getting ready to stall.
The plugs are 'seasoned' to begin with, but running at idle and then stopping, a minute later there is a small amount of fuel on the water. Plugs are a bit wet. Isn't this fairly typical though? Unburnt fuel? It is a 2 stroke after all. Or do you think that I might be getting a misfire that's causing it to stall out in gear?

Compression checked twice on each cylinder in sequence:
Cyl 1: 101 psi/102 psi
Cyl 2: 112 psi/110 psi
Cyl 3: 111 psi/111 psi
Cyl 4: 110 psi/109 psi
 
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Compression is a bit low (could be your tester). Wet plugs at idle in a cold motor is normal. On idle adjustment, the motor has to be fully warmed up and in gear. Find the best idle--go slow and let each adjustment settle in--then ad 1/8th of a turn CCW.

Jeff
 
Also checked timing. In gear at idle was off by one degree (5). Set it back to 4 degrees according to specs. How much will 1 degree affect it?

I set the idle mixture screws to what I could tell was the best idle. Motor warmed up and in gear. If I turn the carbs another 1/8th ccw from where I have it set at the best idle, the motor chokes out and dies. Is this set pretty well?
 
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Was it fully warmed up and in gear when you did this? If not, you'll have to do it again.

Jeff

PS: Good compression for that motor is 120 to 150 (depending on modell years).
 
Yep. Motor ran at idle for 15 minutes in 35 degree weather (that's about 95 to you imperial folks) then put in gear when doing the timing. I went by the Seloc manual word for word to make sure I didn't miss anything.
 
If motor is running right you will not see fuel on water...Most times you will have comp around 120 to 130....
Set your primary timing at 2 degress before TDC, or 2 ATDC
Are your plugs burning all the same, or is the bottom washing clean....

Steve
 
Carbs were both torn down and cleaned/rebuilt about 3 weeks ago. Plugs seem to be burning equally. No noticable difference on any one cylinder. Factory specs for the primary timing is 4 ATDC. Back it off to 2 and see if theres a difference?
 
It seems that carburetion adjustments do not help --------------Timing adjustments do not help.--------------Maybe there is something else wrong with this motor !!!
 
Timing change will help this motor.... I know factory says 4 ATDC, that just a starting point. This motor can run better around 2 BTDC
By moving timing just before TDC gives you better fuel flow then 4ATDC

Steve
 
Had the boat out again on Sunday. All these small adjustments and fiddlin and fartin around with it seem to be helping!!!
Cold start- good. Don't need fast idle, just a bit of choke at the beginning.
Hot start- No problem.
Idle- awesome.
In gear- DOESN'T STALL!!!!!
Thanks a lot guys! This is helping a ton.

I still haven't played with the timing to bring it down around 2 ATDC.
The only issue left is during acceleration. When I accelerate quickly, it revvs up and goes until just before mid power then bogs out and dies. Sounds like it's flooding. But if I take it slow up to the point where it stalls and let it run at that speed for just a second, it recovers itself and I can continue on through to WOT no problem. As fast as I like. Is it more likely that this has something to do with the timing adjustments, or the carbs running a bit rich?
 
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