Yamaha 40V refurb/restoration

[Livid]

Hi all

I'm doing a refit of my 1985 sr4 because the hull is squishy and the transom is... Hollow. A professional boatyard near where the boat is based is doing the hull, but I thought it'd be the time to do some work on the engine. There's nothing wrong with it, just like the rest of the boat it's rather unloved. The previous owner painted part of the cowling bright orange and the leg white. We've kept it well serviced but the has been an occasional misfiring issue and a hole in the lower cowl I bodged with epoxy putty.
Here's a picture of what it looked like, apologies for the blurriness

I decided to lug it from Cornwall to Surrey so I'd be able to work on it for the entire winter, an issue complicated by Hermes losing my stand for it for an entire week. Lugging it to back the of the garage with my dad was an adventure. But anyway we got it up on the stand and took the cowling off to make sure nothing obviously got bumped on the journey

You can see that dodgy repair pretty clearly. About as smooth as my face, or a speedbump.
I'm still waiting for a lot of parts, well my paycheck for the next few months then parts lol so I decided to start work on the cosmetic stuff as I've got plenty of time and sandpaper.
First step was removing the orange paint from the cowl and the air intake cover, encountered my first snapped bolt, this is probably going to be a recurring theme

After a bit of time with the power sander I was making a fair bit of progress

But I decided to work on the rest of it for a while, the white paint was to hide a fair few chips scratches and dings, so I'll be filling them too. Filed and blended the filler in too

This is going to be far more than just a cosmetic job though, I'm spending lots of time making sure it's gonna perform the part too. Current list of mods and tweaks:
New prop
Heavy service
Modified exhaust like the hydrotec kne
New remote and control cables because they're buggered
New throttle linkage and cam because it's worn
Rejetted to 135 and rebuilt carbs
New Reed valves by CCM
Replace gaskets
New cylinder head from tsr products
Balance flywheel
Balance and weld crank
Delete the rev limiter
Open up the cowl to let more air in
3d printed velocity stacks for the carb
New ignition coils from naraku
Iridium plugs and NGK caps without the resistor
Paint engine block
Modify oil pump for slightly higher oil delivery as I'm too lazy to premix
All the cosmetic work

I'll keep updating this post as I progress but suffice to say this'll be a long project, and that's ignoring the inevitable setbacks. This should be very fun once it's finished, if it's ever finished that is

[Livid]

Been working on it the past few weeks, mainly just sanding and filling but also some internals. My naraku race coils have arrived so I made up a wiring loom with extra grounding. They don't fit on the original coil mounts so I 3d printed a little block that lets me mount them the way the stock Yamaha coils mounted.

All the stock wiring is kept so I can go back to original yammy coils if this backfires but I reckon if my crappy wiring holds up it'll work an absolute treat. I'm using NGK plug caps without the resistor because my plugs have them so I should get a lovely strong spark.
Got some teroson/plastic padding marine filler and started work on the ugly bits. The leg has a million and one tiny dinks that look horrific, and the cowl looks bad from when the oil fill cap retainer broke off eons ago. Sanding it all back with 60 grit. I was originally going to go for stock colours but I think I'm going to copy roflhat's beautiful 70hp and go for satin black

I still have to sand back 2 sides of the cowling, the bloody decals are so durable that the cowl ends up bumpy after they're gone so it needs a skim of filler and sanding. I also have to sand the metal intake cover a lot more as it's suffered the elements very badly.
I snapped another bolt under the electrical unit too, need to get some left hand drill bits to get them out, but that's a problem for future me
Finally bought an angle grinder so I can sharpen the skeg and thin it all out for a couple extra knots, and cut the air intake for better flow then it's time for painting. If anyone has any recommendations for durable satin spray paint I'd really appreciate some feedback. My current plan is 2 coats of zinc primer then sand to 240 then a couple coats of grey primer sanded to 800 then the satin paint. Do I need a lacquer for satin paint? What brands should I use?
Also my tsr products cylinder head has landed in the UK but gotten snarled up in customs so I'm going to have to bend over and take it from the taxman.

[Livid]

Some new toys have arrived courtesy of parcelforce and a good mate.
First up is this beautiful hunk of machined aluminium. This is made by tsr products over in Australia, took a while to get it in my grubby mitts (thanks coronavirus). Also had a fun little tax bill thanks to border force but oh well.

This is their head for the yammy 40/50, they also make ones for the tohatsu 50 and a few other engines. They've got loads of useful features like removable combustion chambers, no head gaskets (uses orings instead) and much higher compression. It's also got all the room for the thermal switches etc so you don't lose any of the alarms, big water channels etc etc. Also it looks absolutely stunning 😂😂
I also got this. A Facebook marketplace score, that one of my friends cycled 30 miles to collect whilst I was on holiday

This is the propulse adjustable pitch propeller. I don't know how to prop this engine after tuning so this should be really interesting. Can go from 13" to 17" which should be more than enough for my usage. Blades are replaceable in case I clonk something. Not to mention it looks absolutely vicious! I didn't want a 4 blader but they don't make them in 3 blades so I'll have to deal with it, it should lead to some interesting dynamics, I love being able to trim the nose into the waves for comfort or way out and feel it take off and accelerate.
I'm giving up on painting the cowling myself, I know I'll balls it up and I'd rather my engine not look like a spray can exploded nearby, I will be painting the block myself though, nobody will see that unless something goes wrong haha

[Livid]

Been a busy bee today, stopped procrastinating about it and got busy with the spanners. First thing was fitting all my ignition coils on the loom. I then have Chris applebee engineering a call to get my crank and accoutrements overhauled balanced and welded, courier is picking them up tomorrow so I had to strip the engine down.
First I got the electrical unit off, these yammys are so simple, half a dozen connectors and about 4 bolts and it came right off.

Then it was the carbs and the flywheel. Carbs were easy apart from the prime start solenoids ground connection hiding under the oil tank, when I put it back on I'm relocating that ring terminal as it makes taking the carbs off a pain.
Getting the flywheel off when you have no tools and have the iq of a not particularly smart rabbit is fun, I ended up locking the flywheel with a big screwdriver then went full hulk on the nut. Getting the flywheel itself off was even better because my chinesium pullers were still in the Amazon basket, so instead I applied a small amount of friendly persuasion with a hammer and off she came, as well as the stators and oil seal assembly

Then I had to get the block out, surprisingly no botls snapped today, I wonder if it's been out already as some of the bots are unpainted stainless. It was about this time I started regretting my life decisions and wondering if this thing will ever go back together in one piece.

Base gasket was absolutely shot so putting a new one on will be an enjoyable endeavour.
Lowered the block onto the floor and started removing bracketry and pulling the crank case apart. These little vent tubes are maddening and I'm definitely going to accidentally connect them wrong and explode my engine
Bit more blood sweat and tears and I got what this was all about, the crank and pistons. They're probably ruined from my ape like handling but I digress, time to put them in a box

The bottom bearing sounded rather grumbly so it certainly isn't a wasted effort, should be much happier when I get it back
The parts shelf I requisitioned is now very full, I've done my best to organise the bolts but I know I'm gonna end up with some spares when I put this back together. Of note is how I found 4 washers sitting in the lower cowl after I got the block out, looked like they'd been there for a while 😂

Tomorrow I'm gonna thoroughly check the oil pump, I want to make sure it's free of crud and crap as I want to keep the autolube so the oil needs to flow plentifully, also I dropped one of the washers when I took it off so it needs a clean 😂

[ollyit]

great work looking forward to seeing rest your plan unfold

[Livid]

Originally Posted by ollyit

great work looking forward to seeing rest your plan unfold

Thanks mate, I can't stop worrying that the engine is going to explosively unfold next time I turn the key

[Fenlander]

I know nothing of this engine model so don't know what to look out for or if you're doing what "the experts" would advise.

But I always like seeing things in bits so an interesting thread to me.

[Livid]

Originally Posted by Fenlander

I know nothing of this engine model so don't know what to look out for or if you're doing what "the experts" would advise.

But I always like seeing things in bits so an interesting thread to me.

Thanks man, I've been taking a lot of guidance from roflhat, he's been a godsend, I'd have no idea what to do if it wasn't for him. Indeed it's always satisfying to see big mechanical things in bits

[Livid]

Been grinding on this all week, stripped it back even more which I thought wasn't possible, got to the exhaust tuner and muffler. The muffler will not be going back in one piece haha. Getting to the tuner is a bloody exercise even when the block is out and it's all ripped apart. These joints hadn't been taken apart for 20 years so it was quite un fun to split the leg casing

Bracket is looking very bare on the stand, took the freedom of movement to remove the busted trim sensor, it was all corroded and cracked so the screws were not playing ball. I miiiight have had to bust out the massive flathead and just wrenched it off, my patience for this thing and it's stupid wire was very loe

Then I did a few small other jobs I've been meaning to do, started trying to get the nasty remnants of the base gasket off, had to break out a chisel, then sandpaper to flatten the surface out, I'm going to paint the block before the crank goes back in because I think I'll do a better job without having to worry about masking all that stuff. Also swapped the reeds. I encountered an issue where the reeds were a touch smaller than the Yamaha ones so they didn't seal properly. Luckily Chris over at ccms shipped me some different reeds very quickly after explaining the trouble. Outstanding service and I highly recommend getting performance reeds from him in the future. The original reeds were very reasonably priced too. And fit flawlessly apart from the leading edge, I think it might have been a wear issue or something, my engine is over 20 years old after all.

Then I took a break to return to my nerd cave and designed and printed a set of velocity stacks. These will fit yam 40 and 50 carbs, if anyone wants the file just pop me a pm

Next steps are painting everything and putting the crank back in and then getting it back together. I'm also going to get the carbs bored out to give me a bit more grunt

[Livid]

Been all little jobs this week, waiting for a lot of bigger things to happen so I've done what I can
The electrical unit looked a bit tatty after 20 years, the steel brackets for the relays and solenoids were rusted and the wiring was quite messy. I pulled all the wiring off, starter motor, PTT relay and starter solenoid and took all the little brackets off. Wire brushed the steel relay brackets back to bare metal

After a fair bit of noise and a few sparks they were looking much better so it was time for a few coats of hammerite satin black

Painted the ptt relay too because the casing was corroded and a bit ugly

I then have the aluminium casting a bit of love with the wire brush and a good cleaning, then put it all back together managing the cables much more carefully, looks a lot sharper now.

I also stripped the carbs back because I'm posting them to applebee engineering to get bored out. Because I'm starting with a 40 the carbs are quite restrictive and they'll become a choke point for the rest of the engine. They'll be bored out to 26.2mm, just a hair bigger than the 50 size. Because the castings are quite thin I run the risk of breaking them if I go bigger

I've been looking into getting the lot painted, first body shop I inquired with wanted 1500 quid! That's about what the whole engine was worth 😂😂 I think the hell not. A local garage pointed me in the direction of a guy who was much more reasonable, 300 ish quid. Got a touch more prep work to do, just sanding the final bits of corrosion out then it'll be off for paint next month

[ollyit]

ace work

[Roflhat]

Nice!

[Fenlander]

Amazed at the paint quotes. I've always used rattle cans and obtained a decent finish... lasts for years too and easy to touch up if needed.

[Livid]

Originally Posted by Fenlander

Amazed at the paint quotes. I've always used rattle cans and obtained a decent finish... lasts for years too and easy to touch up if needed.

My skill with a rattle can is absolutely dismal, I'd end up making the floor look better than the engine

[Livid]

Originally Posted by Roflhat

Nice!

Thanks again for all your help mate, this engine would be doomed without all your advice

[Livid]

Been another week of mainly small jobs but some big progress has been made too. Prepped the block for paint, wire brushed off a lot of loose paint, lots of cleaning then a few coats of paint.

Then I got the old head off and the thermal switches out. The surface of the block needed some attention as the gasket didn't come apart nicely, used the blade from an old planer to scrape it very carefully then some 800 grit sandpaper to polish it to a shine. Took this opportunity to replace the internal anodes too, they looked to be in ok condition but this is a really good opportunity

Then I greased the o rings on the new tsr head and installed it all with loctite 572 on all the bolts. Unfortunately I made a bit of a mistake, I forgot to blow out the bolt holes and there was some cleaner in a couple of them. When I was torqueing the bolts down I heard a strange squeaking noise. Turns out I'd pressurised this stuff so much that it split the outer bit of the bolt housing to relieve the pressure. I took the head off and cleaned them all out and went again, I think there was some 572 on one of the little o-rings but I'm sure it won't be an issue. Engine looks really nice now.

This project is gonna be on hold for a little while because I can't do much until I get the crank and carbs back from Chris applebee and I'm headed back to uni this week and I'm not taking the engine with me

[Livid]

Been a while but I haven't forgotten about this millstone around my neck consuming an ever increasing amount of my money, whilst I was at uni I organized getting the engine painted and it looks absolutely fantastic. I ballsed up a lot of the prep so the paint shop had to redo it but it ended up being £480 for the lot which was pretty reasonable

Also got the crankshaft back from Chris Applebee engineering. Theyve done a brilliant job, it looks good as new. I wanted to get it back in over Xmas but I gave my small end bearings a close look and they're a little pitted. Given all the work and money I'm putting into this another £150 for a new set is far from the worst and it means I don't have to worry about it ever again

The stock 40hp exhaust tuner is a totally different shape to the 50 so I just bought a new 50hp tuner, some 40mm box section and I'm getting a welder to join it all up. Going to cost around £170 which is about 1/3rd of what the hydrotec one would have cost me. I'm also swapping the engine mounts because the top one was completely shot and it means I don't need to worry about the engine buggering off the boat
It's the home stretch now, once I get the exhaust welded the whole thing can start good back together. Lots of little trims and so on are going back on already like the anodes and the grills for the water inlet. Once the parts people I use (marine tech, absolutely wonderful people) get back from holiday I can get the small end bearings on the way as well as a couple gaskets and little fixings that rusted away and I can get the block back together and on the leg. Then just need to service the lower unit (impeller and gear oil) and I should be able to turn the key! If it works I can start wasting my money on something new. My cousin revealed him and his dad have a bet on whether or not it's ever going to work again haha

[Spreu-boote]

Wow you are going really pro on this restoration with a lot of expenses. Will it in the end be cheaper than buying new or do you have other/better reasons for this restoration?

Kind regards, Kees

[Livid]

It's worked out as being about £2.5k ish, so you could get a decent used one for the same money. I'm doing it mainly for the challenge and because it's interesting.
There was nothing strictly wrong with the engine when I started, it was just a bit tatty. I'm getting the rib redone this winter too so I thought I should have an engine that looks the part. I could have gone for a used 4 stroke but my opinion of them has been tarred by a Yamaha f40f that just wouldn't work for years. We got it sorted, ended up being mainly mechanic incompetence but the 2 strokes just run like clocks and I thought it'd be cool to get loads of extra power without having more weight

[Spreu-boote]

Originally Posted by Livid

I'm doing it mainly for the challenge and because it's interesting.

I totally understand. Worth every penny