Submerged Outboard – Revived / Frozen / Revived Again

[mike]

Near the end of our last big trip a month before Katrina, we encountered a thunderstorm that flipped our towed dinghy (along with the little Johnson 3.5hp outboard I had foolishly left on it). As soon as I got home, I flushed it thoroughly with WD40 (after draining the water out of the cylinder!), and was pleased when I was able to get it started. I let it run for a half hour or so, then put it back in the garage.

After the hurricane, boating was the last thing on my mind, and I didn't touch the motor until several months later when we were moving, only to find that it was frozen up (tried pulling the starter rope, wouldn't budge at all). Great, it's ruined... but I couldn't bring myself to throw it away.

Fast-forward a couple of years to today... I decided to fiddle with it, figuring I had nothing to lose. I pulled the spark plug off, and filled the cylinder with WD40. After letting it soak for a while, I put a socket wrench in the spark plug hole and gave it some taps with a hammer... the piston moved down a bit. More WD40, with some tugging on the starter rope, more tapping, and manually turning the prop yielded a gradually increasing range of piston movement, until pulling the rope resulted in normal cranking.

I put the spark plug back in, filled it up with fresh gas/oil, and after fixing an overflowing float bowl (stuck needle valve), the little motor started on the first pull.

--Michael

[kmclemore]

Great job getting it going again!

My suggestion now would be to run it for a little while until it's fully warmed up and then change that oil again, because the oil will have become contaminated by the rusty swarf rubbed off the cylinder walls. Then, before storing it again, use a quality fogging solution before shutdown and drain out all the petrol.

Also, a safer way of knocking down that piston is to use a hardwood dowel rather metal (your wrench)... it prevents accidentally damaging the piston crown... if it doesn't move with the hardwood, then a second choice would be to use an aluminium drift pin, but I like to avoid metal altogether if I can.

[pokerrick1]

Gosh- - - SOMETIMES I wish I knew half of what Kevin knows about this stuff

Rick

[mike]

My suggestion now would be to run it for a little while until it's fully warmed up and then change that oil again, because the oil will have become contaminated by the rusty swarf rubbed off the cylinder walls. Then, before storing it again, use a quality fogging solution before shutdown and drain out all the petrol.

Actually, it's a little 2-stroke motor, so no oil to change. But now that it's revived, I'll make an effort to store it properly.

Also, a safer way of knocking down that piston is to use a hardwood dowel rather metal (your wrench)... it prevents accidentally damaging the piston crown... if it doesn't move with the hardwood, then a second choice would be to use an aluminium drift pin, but I like to avoid metal altogether if I can.

Eeeek... well, I hope I didn't screw up the piston.

--Michael

[Moe]

You did change the gear oil in the foot, right?

[kmclemore]

My suggestion now would be to run it for a little while until it's fully warmed up and then change that oil again, because the oil will have become contaminated by the rusty swarf rubbed off the cylinder walls. Then, before storing it again, use a quality fogging solution before shutdown and drain out all the petrol.

Actually, it's a little 2-stroke motor, so no oil to change. But now that it's revived, I'll make an effort to store it properly.

Also, a safer way of knocking down that piston is to use a hardwood dowel rather metal (your wrench)... it prevents accidentally damaging the piston crown... if it doesn't move with the hardwood, then a second choice would be to use an aluminium drift pin, but I like to avoid metal altogether if I can.

Eeeek... well, I hope I didn't screw up the piston.

--Michael

Ahh, right - I don't know the smaller motors that well, so I missed that it was 2-stroke. In which case, you'll want to increase the oil ratio in the fuel, as per the normal break-in instructions for 2-cycle motors (usually double the ratio - for example 25:1 instead of 50:1), and vary the engine speed during the warm-up. (There's a handy oil/gas ratio calculator here). It will take about an hour's running to fully run-in the motor after a seizure.

As far as screwing up the piston, that really depends on how hard you whacked it, and how sharp the metal object was! The two things that could end up going south by using a metal object to free a stuck piston are that (1) you may crack or dent the piston crown resulting in premature failure, or, (2) you may create a 'burr' of raised metal on the crown which will then get hotter than the piston and cause pre-ignition, with the possibility it can ultimately 'hole' the piston. Here's an example (from my shop) of the damage from pre-igniton:



Not pretty! (The piston is from a 1966 Triumph 2000.)

[mike]

You did change the gear oil in the foot, right?

Uhhhhhhhh..... no. Thanks for the reminder!

--Michael

[mike]

Ahh, right - I don't know the smaller motors that well, so I missed that it was 2-stroke. In which case, you'll want to increase the oil ratio in the fuel, as per the normal break-in instructions for 2-cycle motors (usually double the ratio - for example 25:1 instead of 50:1), and vary the engine speed during the warm-up. (There's a handy oil/gas ratio calculator here). It will take about an hour's running to fully run-in the motor after a seizure.

Thanks for the info... I only ran it for 15 minutes or so yesterday, and with a slightly higher oil ratio. I'll make it 25:1, and will run it for an hour this weekend.

As far as screwing up the piston, that really depends on how hard you whacked it, and how sharp the metal object was!

Hopefully it will be ok... I used the tail end of a socket wrench, which was sort of "rounded". I'd describe the hits as "hard taps"... one-handed, with a normal hammer (as opposed to clamping the motor into a vise and slugging it two-handed with a maul).

--Michael