Mercury 60hp (mid-80's) stalling

[Fishcake42]

Hi guys, kicker sorted, now on to the main engine.

3-cyl, twin carb 2 stroke Merc. Still trying to narrow down the symptoms, but the main element is stalling. Last trip out would stall under load if attempting more than idle throttle. Testing at home in tank will now run under load, but stalls with rapid return to low rpm/idle.

Would sometimes start no problem straight after, other times not. Tested with new internal fuel system, and with stand alone tank and primer, confident it's engine related. Fuel pump tested (diaphragm good) fuel flowing, not a huge stream but it flows. Carbs cleaned thoroughly and blown through, floats adjusted and mixture returned to average (1.5 turns). Good compression (123/120/120), whilst writing realised I didn't get round to the spark test today (will do and update).

Engine new to me and I think previous owner was a bit happy with adjustments as have found a Number of things way off spec (and the assurance that the carbs had been rebuilt recently was nonsense) First question is could this be timing related or would you guys be looking elsewhere?

 

[achris]

Re: Mercury 60hp (mid-80's) stalling

Those engines are particularly susceptible to worn spark plugs. Take all the timing and sync settings back to factory, throw in a new set of plugs and go from there.

Chris....

 

[Fishcake42]

Re: Mercury 60hp (mid-80's) stalling

Many thanks Chris, read your mind as ordered a new set of plugs last night just after posting. Will do a link and sync up next weekend in line with the manual. Grateful for the response, really quick.

Not that it matters, forgot to add that pumping the primer doesn't help the stalling state, hitting the enriched stalls it too - which although in my mind indicate a rich state could be weak spark being flooded.

Anyway will update when done, thanks

Matt

 

[achris]

Re: Mercury 60hp (mid-80's) stalling

..Not that it matters, forgot to add that pumping the primer doesn't help the stalling state, hitting the enriched stalls it too - which although in my mind indicate a rich state could be weak spark being flooded.

Anyway will update when done, thanks

Matt

That's a really good test. If that didn't help, then it's likely an ignition problem...

BTW, which manual do you have? (OEM or aftermarket)

Cheers......

 

[Fishcake42]

Re: Mercury 60hp (mid-80's) stalling

I think its aftermarket covering 40hp - 115hp up to 1989. Don't trust cowling, and Seriel no is Belgium built so hard to pin down model and year. Went mostly by the drawings and photos of internals to confirm correct. Also have a seized 70hp Blueband for spares and comparison (has same head, ignition and carbs. I'm used to working on inboards (big ones), but as an observation - I know the timing should advance before the butterfly's open but it looks to advance a hell of a lot before they do. Link and sync to be sure. Happy to be proven wrong.

 

[achris]

Re: Mercury 60hp (mid-80's) stalling

Post the serial number, I may be able to narrow it down for you... What I can tell you is that the 3 cyl 60hp started in 1984...

 

[Fishcake42]

Re: Mercury 60hp (mid-80's) stalling

Will get the wife to check it, away on business at the moment and will post later on. Thanks

 

[Fishcake42]

Re: Mercury 60hp (mid-80's) stalling

Serial no. Is 9537349

 

[carholme]

Re: Mercury 60hp (mid-80's) stalling

That s/n comes up as:

60 60 3-cyl 9506191 9549298 1988 Belgium

From here:

Mercury 2-takt, 3-cyl, 60 - 90 hp, produktions?r, modellguide

Parts List for s/ns 9469200 thru 9683054:

50/60 H.P. - Mercury, Mercruiser, Force, etc. Parts Lookup

The manual you require should be 90-86135--5

Gerry

 

[Fishcake42]

Re: Mercury 60hp (mid-80's) stalling

Many thanks for help so far. I shall confess that having now studied the sync process in the manual, and trawled other threads, it seems that in reality the process is straight forward, but it's all down to having good guidance (the non-pen manual had a full-some description but I need to be looking at the engine to make sense of it. Will do all this at the weekend, but I would appreciate any top tips. Top amongst them already seems to be the timing itself (flywheel position) is extremely unlikely to have changed so the focus should be mainly on idle and max timing and carb butterflies. Does a 1988 have clear marks/degrees on the flywheel?

M

 

[Fishcake42]

Re: Mercury 60hp (mid-80's) stalling

UPDATE:
All adjutsments completed (previous owner had mounted the cluster pin the wrong way round hence the carbs opening so late. Max spark now at 21deg BTDC, carbs open at 4degBTDC. Idling well, runs up the throttle range and back down to idle no problems. A couple of tweaks on the water. Tacho on its way, but no crunch when going in to gear, so happy its below 1000rpm.

One quick question, tell-tale water used to be "hot", could touch it but it was uncomfortable. Now is warm and constant. Would you agree that timing and carbs being so far out (max spark was 30degBTDC) would cause an overheating state? Just for my own reference in the future as a diagnostic symptom.

M

 

[achris]

Re: Mercury 60hp (mid-80's) stalling

It's possible, but I wouldn't rely on it as a diagnostic tool...

Chris.......