Anyone here good with outboards?

[Guineafowl]

Evinrude 70 VRO (with VRO disabled) 1986.

Original problem was, it will idle when on muffs, but not in the water. Turning up the idle speed sorted the problem temporarily, but clonking into gear at fast idle is not good for the gearbox.

Slight fuel leak from the pump into the defunct VRO bit. I think it’ll need blanking off. Pics to follow.

Changed fuel lines, carb kits, plugs.

Cheers

 

[Bullet2012]

They make a reasonable anchor

 

[Guineafowl]

They make a reasonable anchor

Duly noted

 

[Rannsachair]

Running on all cylinders at idle?

 

[Guineafowl]

Running on all cylinders at idle?

On the muffs, it seems to idle all all cylinders. In the water, just dies, which makes manoeuvring tricky.

I can sort the fuel pump, and the carb kits are done. Someone suggested it might need the carbs balancing and perhaps the ignition timing set, which I can’t do.

Alternatively, there might well be a very nice 18ft Icelander for sale, with above Evinrude and spare Mariner 9.9, as I’m not getting much use out of it.

 

[Rannsachair]

You have back pressure on exhaust in the water, so lowers idle a bit. Best testing in a large drum

Have you checked compression?

 

[voipio]

Had something similar with a Mercury 2-stroke outboard. Turned out to be a faulty ignition coil. It might be worth taking the spark plug leads off and meauring the HT coil resistance. Mine was open circuit.

Presumably it's running on premix, if the VRO is disabled. What fuel to oil ratio are you using?

 

[8ob]

A vacuum pump is your best friend when it comes to two strokes. A wooly idle smacks of duff crank seals, a vac pump/gauge some plugs/blanking off plates and go through the individual cylinders.

Bob

 

[Guineafowl]

Compression - I can’t remember the figures, but one was just outside the 10% range of the others.

I’ll check the coils, thanks.

50:1 fuel.

Crank seals a good suggestion, but the problem is the same as the compression: I’ve tarted up a few engines by glaze-busting the bores and fitting new pistons and rings, but I doubt the bolts will undo at this age.

 

[addjunkie]

Have you checked your idle jets arent partially blocked, and in turning up the idle speed actally started opening main jets, also look for needle wear in the carbs. Old outboards are hatful things.

 

[Guineafowl]

Have you checked your idle jets arent partially blocked, and in turning up the idle speed actally started opening main jets, also look for needle wear in the carbs. Old outboards are hatful things.

Carbs have been stripped and blown out twice, so hopefully not. Carb kits didn’t include needles/jets but didn’t look too worn.

 

[minimutly]

You have back pressure on exhaust in the water, so lowers idle a bit. Best testing in a large drum

Have you checked compression?

Lol, wet feet. Btdt

 

[Keith 66]

I have had several outboards that would run fine out of the water but not on the boat, in all cases it was crankcase seals had gone too much back pressure on exhaust means it wont suck petrol into the cylinders.

 

[Guineafowl]

I have had several outboards that would run fine out of the water but not on the boat, in all cases it was crankcase seals had gone too much back pressure on exhaust means it wont suck petrol into the cylinders.

You and @8ob have suggested crank seals. If I had the exhaust under water, and made a fitting to go in a spark plug hole, to take a vac/pressure pump, would that suffice?

Would you attempt stripping a 1986 outboard to change the seals? I can just imagine every bolt shearing.

 

[Keith 66]

Outboard bolts are made from a special steel lead alloy designed to break, assembled at the factory with no anti seize goop salt water & corrosion between the steel & alloy will mean bolts are easy to snap off. Heat them up first with a small butane torch & plenty of plus gas & you may get lucky.
I have always snapped at least one & ended up drilling it out or picking it out in various ways!

 

[Barking Mat]

I don't touch outboards, fiddly PITA things.

My boss knows his stuff.

If it's not Yamaha or Honda, he describes them as anchors.

 

[8ob]

You and @8ob have suggested crank seals. If I had the exhaust under water, and made a fitting to go in a spark plug hole, to take a vac/pressure pump, would that suffice?

Would you attempt stripping a 1986 outboard to change the seals? I can just imagine every bolt shearing.

I wouldn't strip anything at this point but I would just check the integrity of the crank seals,a bung or plate over the inlet /exhaust port and introduce a vacuum, one of the bungs/plates will need a hose barb to attach the vac tester tube too. Simple stuff, make a decision to strip,overhaul or convert to an anchor after the the test.

Bob

 

[Keith 66]

You might be lucky, we have a 2Hp Mariner, it dates from 1980, It had been hanging in the roof of father in laws workshop for donkeys years & we started using it a few years back. Last weekend it seemed to be running a bit hot so a strip down was in order.
I thought it would be a sod & that i would break bolts galore but no. Every single bolt came undone with just one requiring a bit of heat from the butane torch before it came free. I dont think it has ever been apart before.
Every waterway was absolutely solid with caked crud & salt & its a wonder it never seized.
All cleaned out now & will put it back together tomorrow.
Result!