Milky engine oil, 4 stroke

[beamishken]

Originally Posted by Tommy c

Complete tear down??

My guess would be you will find significant salt buildup & corrosion in all the water galleries my money would be on the base gasket where the powerhead meets the leg & the sump bolts on. Might be headgasket but if I was doing one I'd definitely do the other at the same time. As Pd says you've nothing to loose apart from a little time & potentially the opportunity of selling it as spares & repairs. When looking at adverts for spares & repairs many folk think ahh its only a head gasket when in reality these things tend to grow arms & legs when you start stripping them & once you strip it you've removed all doubt that its repairable & its only good for spares unless your very lucky.
My pal managed to patch one up with jb weld for a couple of seasons where it had rotted through the caseing.
If you have time & inclination it doesnt take long to strip one, you might be lucky & find its not that bad
I definitely wouldn't consider paying someone to investigate you'll spend more than its worth

[spartacus]

Originally Posted by Pikey Dave

You’ve nothing to lose. Dismantle it, investigate, re-assemble, learn.

That should be a sticky on the site!

Cost is a price of full set of gaskets, thermostat and carbide drill bits when a bolt breaks. A can of PlusGas penetrating release and blow torch is essential.

[neil.mccrirrick]

It’s never hard to take apart. When you look at all the bits when it’s apart, that’s daunting [emoji1]

Take photographs as you go. They will be invaluable when it comes to rebuild

Most things are made so they only go back one way.

[Tommy c]

Originally Posted by beamishken

My guess would be you will find significant salt buildup & corrosion in all the water galleries my money would be on the base gasket where the powerhead meets the leg & the sump bolts on. Might be headgasket but if I was doing one I'd definitely do the other at the same time. As Pd says you've nothing to loose apart from a little time & potentially the opportunity of selling it as spares & repairs. When looking at adverts for spares & repairs many folk think ahh its only a head gasket when in reality these things tend to grow arms & legs when you start stripping them & once you strip it you've removed all doubt that its repairable & its only good for spares unless your very lucky.
My pal managed to patch one up with jb weld for a couple of seasons where it had rotted through the caseing.
If you have time & inclination it doesnt take long to strip one, you might be lucky & find its not that bad
I definitely wouldn't consider paying someone to investigate you'll spend more than its worth

It won't be salt corrosion Ken. It's a 2004 model and I know for sure it's been on a freshwater lake for at least 15 years
It pumps water like a hydrant

[Tommy c]

Anything in particular I need to be mindful of when stripping?
I normally use marine.com for explosive diagrams but they don't list honda

[beamishken]

Originally Posted by Tommy c

It won't be salt corrosion Ken. It's a 2004 model and I know for sure it's been on a freshwater lake for at least 15 years

It pumps water like a hydrant

Didn't realise it was a freshwater one maybe not as bad as I expected you may be lucky.
Not much to be wary of when stripping it, if its freshwater then less likelyhood of snapped bolts but still need to go careful & be prepared to use a little heat if you feel ones not coming out. Only thing a little more complicated is the cam timing, check for marks before you lose the timing between crank and cam, usually dots to line up mark things up if your unsure.

[Tommy c]

Originally Posted by beamishken

Didn't realise it was a freshwater one maybe not as bad as I expected you may be lucky.
Not much to be wary of when stripping it, if its freshwater then less likelyhood of snapped bolts but still need to go careful & be prepared to use a little heat if you feel ones not coming out. Only thing a little more complicated is the cam timing, check for marks before you lose the timing between crank and cam, usually dots to line up mark things up if your unsure.

Yes it's the timing I am concerned about.
I know it was still being used up to and including last year so it's been unused now for 12+ months

[Peter_C]

"Test don't guess". I would still perform a cylinder leak down test, but I have the tools to do so. Not knowing the water passages for the BF5A is it possible the water is getting into oil from somewhere other than the headgasket? Like from a port that connects the water jacket to the oil? Is the headgasket corroded on the outside of the block where you can visually see it? What does the spark plug look like? Is it a tan color or white around the electrode? Is the top of the piston clean aluminum when you look in with a flashlight?

Could you find a way to very lightly pressurize the cooling system by dropping the lower leg and see if the crank case is getting pressurized?

I just went and looked at my BF5A to see what is involved for cylinder head removal. The power head must be removed from the case prior to removing the head from the block. My guess is about 30 minutes of tear down time, but mechanical knowledge will be needed. The motor is very simple. There are a lot of "tricks of the trade" to make sure everything goes smoothly though.

OP is this something you are up for?

[Tommy c]

Originally Posted by Peter_C

"Test don't guess". I would still perform a cylinder leak down test, but I have the tools to do so. Not knowing the water passages for the BF5A is it possible the water is getting into oil from somewhere other than the headgasket? Like from a port that connects the water jacket to the oil? Is the headgasket corroded on the outside of the block where you can visually see it? What does the spark plug look like? Is it a tan color or white around the electrode? Is the top of the piston clean aluminum when you look in with a flashlight?

Could you find a way to very lightly pressurize the cooling system by dropping the lower leg and see if the crank case is getting pressurized?

I just went and looked at my BF5A to see what is involved for cylinder head removal. The power head must be removed from the case prior to removing the head from the block. My guess is about 30 minutes of tear down time, but mechanical knowledge will be needed. The motor is very simple. There are a lot of "tricks of the trade" to make sure everything goes smoothly though.

OP is this something you are up for?

I may as well have a go.
I don't particularly need it and it doesn't owe me anything.....yet.
Would the outboard manage to run for 30 minutes and still be able to start up first pull everytime if the head gasket was blown?

[beamishken]

Originally Posted by Tommy c

I may as well have a go.

I don't particularly need it and it doesn't owe me anything.....yet.

Would the outboard manage to run for 30 minutes and still be able to start up first pull everytime if the head gasket was blown?

It could run fine & the gasket still be failed between an oilway & the water jacket but the fact a single cylinder engine runs suggests the compression sealing part of the gasket is in tact. Its a fairly major breach between waterjacket & crankcase somewhere, might as well just strip it, your not going to achieve much doing further testing.

[User name]

Originally Posted by Tommy c

Would the outboard manage to run for 30 minutes and still be able to start up first pull everytime if the head gasket was blown?

Compression is likely still good, hence why it still starts, but test it to confirm.

With the rate it filling the oil with water, my money is on a breakdown at the gasket separating the water jacket from the pushrods. If that's the case, it's a fairly cheap and easy fix.

[Tommy c]

Originally Posted by User name

Compression is likely still good, hence why it still starts, but test it to confirm.

With the rate it filling the oil with water, my money is on a breakdown at the gasket separating the water jacket from the pushrods. If that's the case, it's a fairly cheap and easy fix.

SO head gasket or power head base gasket are favourites??
Or the head cover gasket?

[Tommy c]

Originally Posted by beamishken

It could run fine & the gasket still be failed between an oilway & the water jacket but the fact a single cylinder engine runs suggests the compression sealing part of the gasket is in tact. Its a fairly major breach between waterjacket & crankcase somewhere, might as well just strip it, your not going to achieve much doing further testing.

SO head gasket or power head base gasket are favourites??

[spartacus]

Originally Posted by neil.mccrirrick

It’s never hard to take apart. When you look at all the bits when it’s apart, that’s daunting [emoji1]

Take photographs as you go. They will be invaluable when it comes to rebuild

Most things are made so they only go back one way.

Good call. Tupperware dishes for bolts and label parts with an indelible marker such as a series of dots if bolt sizes vary.

If the OP does go for a complete strip down then you’ll need new bolts for cylinder head, and there’s a tightening sequence, usually from the centre out to a finished torque setting. Don’t use a screwdriver to lever off the head under any circumstances. The gasket will be well and truly bonded, but take your time.

[beamishken]

Originally Posted by Tommy c

SO head gasket or power head base gasket are favourites??

For what it takes I'd do them all they will probably come in a kit anyway.
I'd favour base gasket but to be honest its just guessing until you take it apart.

[User name]

Originally Posted by Tommy c

SO head gasket or power head base gasket are favourites??
Or the head cover gasket?

Head gasket is where I would be looking.

[smallribber]

Originally Posted by 69cmw

It’s 20 years old. Scrap it ��

Never do that. Older is very Offton better. Try to fix it, It might be easy and at the very least you will learn and become more brave when you might need to fix something larger and not free. At the very least if you cant fix it. once stripped down you might be able to sell the spares on eBay.

If you do fix it you will have a massive feeling of achievement. If you cant at least you tried