1986/7 Mercury beeping at me

[Crezzlin]

Hi guys any advice please, i have a 1986 model Mercury 135hp v6 2stroke.

My problem is mow that i have found the fuel leak been a split pipe after boat was sitting all winter but did run fine last year..

now the motor will rev out at 4,000rpm and just sit at that. even feels sluggish getting to 4k, then after about 30 seconds the engine does a continuous beep at me, i have a feeling the tell tail water feels a little hot, but it does flow strong, can the two be linked or does it sound like no oil or something. the motor will idle fine, cant 100% tell if on all cylinders but doesn't sound ruff. thanks

[paddlers]

Evidently beep beep beep contantly is oil and one long beeeeeeeeeeeeeeeeep is heat/water temperature which on my V6 Mariner is the two brown wires running to sensors on the top of the cylinder heads.

[jambo]

Originally Posted by paddlers

Evidently beep beep beep contantly is oil and one long beeeeeeeeeeeeeeeeep is heat/water temperature which on my V6 Mariner is the two brown wires running to sensors on the top of the cylinder heads.

No constant flash is wster check your tel tale. If your burning oil and you have a normal tel tale then you have a wiring fault

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[cptsideways]

Our random beeping is caused by wiring in the controls (where the beeper is) on our 90hp Mercury 2st

[9D280]

Originally Posted by jambo

your burning oil and you have a normal tel tale then you have a wiring fault

....or a mid 80s 2- stroke!



This is no more than gut feel, but as your engine is of 1986 vintage, I would guess that beep is either low/no oil or high temp. Working telltale would hint the water pump is OK, but what about your thermostat?

Assuming it's an auto mixing engine check the oil tankthat the float on the level gauge hasn't sunk. (assuming you have topped the tank up). While you are poking about - check all the electrical connectors - It;s wiorth pulling & re- connecting - on those bullets the F side sometimes needs a wee squeeze to make sure of a good connection.

[Crezzlin]

Thank you guys.

After sitting over winter it wouldn't run and fuel was leaking from a split pipe and 2 of the carb overflows were spitting out fuel, after a quick blow out and replace the broken fuel line she starts..

My main worry is 1 lack of smoke, 2 engine will not rev above 4k on the water but does stay steady at that, 3. The beeping

If I remove thermostat this may help with the overheating alarm but not fix the problem, could it be a case of no fuel or oil getting to some of the cylinders this then holding back my rpm and causing the overheating in the cylinders that have no oil/fuel..

I will get down tomo and remove thermostat and check all plugs for sparks..

Wouldn't it just seize from no oil? Only think I could think was the engine was holding back due to overheating but as its a 86 model do the electrics do this as a safety measure or not.. Sorry about the text, on my mobile Thanks

[9D280]

Originally Posted by Crezzlin

Thank you guys.

After sitting over winter it wouldn't run and fuel was leaking from a split pipe and 2 of the carb overflows were spitting out fuel, after a quick blow out and replace the broken fuel line she starts..

Spitting out fuel?
Did it still do that when it was running?

Originally Posted by Crezzlin

My main worry is 1 lack of smoke, 2 engine will not rev above 4k on the water but does stay steady at that, 3. The beeping

Does the beeping start as soon as you put the key to the "run" position, or does it wait a while before it starts?
Instant I would be checking the thermal switch, wait would hint it may actually be a temp related problem - IF that is what the beep is about! (may be oil level related if it's an auto mixer)

Originally Posted by Crezzlin

If I remove thermostat this may help with the overheating alarm but not fix the problem, could it be a case of no fuel or oil getting to some of the cylinders this then holding back my rpm and causing the overheating in the cylinders that have no oil/fuel..

Agreed - also removing the thermostat will likely cause it to idle rough as the proverbial badger's posterior. (says he trying to keep it polite! )

First let's see if it's the temp switch. Have a look round your cyl head. There will be a round thing, probably with 2 wires but maybe only 1 , buried in a recess. Disconnect it, click your key to "on" (this is basuically a "live" test of the sensor, wthout the engine runing). Apologies for the basic- esque way of writing the next bit....

A
If it beeped from "go" before, has it now stopped? if yes, go to "C"
If it waited for a bit before, does it do the same thing? - If Yes, go to "B", if no, Go to "C"

B
Probably not the temp switch, seeing as we have just removed it form the circuit.

C
Take the 2 wires & touch them together. does that start the beeping? If Yes - D If No E

D
Reconnect the wires to the switch, if it beeps again, your switch is jammed i nthe "hot" position - replace it.

E
It's probably not the temp switch.....


Quick background - these overheat switches are basically bimetallic strips a bit like an old style room thermostat. If it's jammed in the "closed circuit" position, the alarm thinks the engine is too hot. Nothing high tecch - it literally just earths the buzzer to allow it to buzz.

Originally Posted by Crezzlin

I will get down tomo and remove thermostat and check all plugs for sparks..

Also have a search (recent post) for spark testers..... Spark is one thing, decent spark is a whole different kettle of fish.

Originally Posted by Crezzlin

Wouldn't it just seize from no oil? Only think I could think was the engine was holding back due to overheating but as its a 86 model do the electrics do this as a safety measure or not.. Sorry about the text, on my mobile Thanks

No oil seize - yes.

On an engine that age I doubt it, but there are may other things would make it run lethargically, including too much fuel.


Have you looked at your prop? How manky is the inner (exhaust) hole? Lots of soot / unburnt oil would hint one cyl not firing. a straight 3 would barely make 2K with one cyl down, a V6 has a lot more "spare" if one dies.

Also when were the plugs last changed?

[Crezzlin]

Fantastic

I’ve still to get down to my boat, work keeps holding me back but soon as i do i will use your guide 9D280

Originally Posted by 9D280

Also when were the plugs last changed?

I changed the plugs last year, had about 2hrs use before sitting over winter, soon as i get to the bottom of this; I’m going to remove the auto oil system, any advice needed? or is it straight forward unplug wires and tanks etc.

One other thing, i don’t have a clue Does the oil get mixed with fuel after or before the carbs?

[9D280]

Originally Posted by Crezzlin

I’m going to remove the auto oil system, any advice needed? or is it straight forward unplug wires and tanks etc.

Probably. For sure you'll need to airtight plug thre injection point(s) and probably confuse the engine into thinking it has oil / flow by bypassing / substituting the tank level sensors & oil flow sensor(if fitted).

Also worth a sticker by the fuel connector pointing out it's not autolube so someone who "knows that type of engine" doesn't feed it neat fuel.


As an aside, if it works OK, there is an argument for leaving it be- one downside to premix is that it only needs one tiny petrol spill & your deck becomes a skating rink.... (dont ask me how I know... ) Also you need to carry spare oil & a method of measuring it if you go cruising & need to top up......

Originally Posted by Crezzlin

One other thing, i don’t have a clue Does the oil get mixed with fuel after or before the carbs?

No idea. Depends on the engine. My old Suz was after, I've also seen before - Only sure way to find out - Follow the oil pipes!