For years I was a big British auto fan until family and education got in the way.
I was a British car fan from the time I became a teen. My parents rented a house to a locally rising lawyer who had an MG-TD that lit my fire so by the time I was 15 I got an 1957 MGA to restore with my uncle's help and guidance it was on the road by the time I was 17. It was raceboats and cars from there on. I got wiped out by a drunk driver the same year I got the MGA on the street but I kept going. I had a whole series of British sports cars through the years as a weekend fun car until it finally ended with a Rover 3500 V-8 with the 3 working hood scoops in the early 1980s. After some near misses driving motorcycles too my wife had a serious discussions about my toys so she (she drove some hydro herself) encouraged me to stick with the raceboats as she saw safety on the water as opposed to concrete and some one else's iron crashing into me on the street. I have had no auto accidents since the time of what happened to my first MGA. In retrospect all those British cars I had would be worth a collectors fortune today. Now I stick to British Anzani and other outboard racing engines and theri boats as the serious hobby. Isn't hindsight great! :)
Back to your hydro and Merc. From the setup I made for myself to handle the Merc engine without having to alter its internal carb and mag throttling and hanging a very simple setup on the exterior where it should be using modified normal hookup parts cables and a dead man's throttle coupled to a lever separate shifter for engine neutral and forward is the easiest, cheapest, simplist and safest way to go. I wish I took some pictures of the on side of the motor hookup but I didn't but I did make it adjustable at side of the motor and once set you could use the setup on any size of Merc 4 cylinder from 30, 40 or 44 cubic inch range short shaft engine. (advice, stay away from Merc/Mariner 2 carb, 49 cubic inch 3 cylinder engines, they were the worst lemons imaginable you can't give away here because of their chronic overheating problems there is no way to rectify).
Why I took out reverse was a matter of safety. With little freeboard at the stern of most hydros putting the engine in reverse could toss water over the transom and even pull the transom down and under given trim conditions and weight distribution in the boat with driver, fuel load and battery for me. Being careful you will not miss reverse anyway. One other thing is that even though my hydro set up this way does mid 50 mph speeds I still wear a approved life jacket and crash helmet as you can count on yourself to take great care but it is usually some other fool in a boat that does it to you. Even here in our wide open spaces of North America there are some real idiots out there who create on water crashes so bad even killing people at times you wonder who licenced them to drive a boat, jetski or car for that matter. Last accident we just had here some fools crashed into a big bridge pier in the dark doing 40 miles per hour on the Red River here and had no lighting.
Drop me a line or email as you progress with your hookups but as I am sure as you study the normal hookups at the engine with the actions of using an old standard throttle hookup you will see just how easy it is to adapt that system easily and cheaply to you adaptation to a dead man's throttle.
If you find it hard to items like a dead mans tethered magento kill switch (uses normally open mode, when tether is pulled goes into closed mode grounding the magneto points to its frame) I can give you website into here to get what you need. The snowmobile industry is full of that aftermarket stuff.
One thing before I log out of this post is that with a hydro and your stock setup the miles to the gallon performance can unbelievably extended. Once your on plane with a decent prop I found on the 3 gallon gas tank I was running you could almost double your mileage once you got the hydro on to plane and figured at what speed you wanted to cruise it. I would carry an extra fuel can with about a gallon just for the safety of having an added reserve to get back to the boat launch area.
I hope I have helped and will continue to do so.
Nice job but more strengthening needed on the tower
That is a lot of nice work on the tower. Because of the top brass spout on top that identifies the tower as pre-Merc 55H. The casting is thinner and cracking prone especially where previously welded, than the thicker cast 55H so buttressing with welded on plate buttresses from just below the block to tower engine bolting with the added buttess plates being welded to the top of the cavitation plate are really required. I have had my fill of KG9 and 40H racing towers cracking and I have lost entire gearcase and prop to a midsection breakoff that had been welded that occurred when I did not add on buttressing on both sides loosing everything below the repair weld. These added buttresses can be made to look very much as part of the racing engine with clean welds and nice grinding and filling. Believe me strengthening the tower with these buttresses on each side are essential.
You are sure well on your way that is for sure. The engine is shaping up nice! And its a Merc modified! lol! :):)
I see the recoil top a bit better now.
The recoil is definitelyoff a later model Merc 4 cylinder cut and pasted to fit the Mark 40 top. Other than the housing the Mark 40 and Mark 55 early recoil systems are virtually the same so that is why the cut and paste is on your Mark 40 and would work. Mark 40s start quite easily with a rope on their recoil start basket sheeve too, so if you went that route to look a bit more Modified and racy that would be okay too.
If your overhauling the engine innards, bearings, new rings, seals etc. there are aftermarket sources for most at way less a cost than OEM stuff that is very hard to get so looking at aftermarket alternatives would be a first consideration. Nice thing about Mark 40s is that you can use later Merc Mk55-Mk55H connecting rods (even a later crankshaft can be fitted with some small flywheel and cogged belt drive) and later model flat top pistons if it does not have them already that would raise the compression a bit more giving some more performance. That Merc emblem parked in there is from the front cowl face plate of a Mark 55.
Not that long ago I saw a 4 tube megaphone Quincy pipe set and filler block for sale quite reasonably that would sure give your engine a nice racing touch but there in UK starting up a race engine on open pipes would sure get you attention that some would like making things exciting as if an F1 open wheel race was going on in town but on the other side they might hustle you off to the local jail house for a stay in solitary in a rubber room too! LOL! There are some double standards there where certain motor sports run racing exhausts and on the other side there are people like us once they hear us they just smack a inked rubber stamp on your forehead with the word "NO"! :)
Steve, your right on it, strengthening and all.
Steve:
Your on the right track when it comes to strengthening that tower on the sides and the area from the water level snout and to the brass outlet plug. I wished I took pictures but they would have been the least ones taken. I sure didn't want a picture of what happened to me when one of my 40H towers broke where it was welded, the re-welded and it still ended up parting and loosing the lower unit and prop along with it about 85 miles from here at a place called Lee River. Your going way further in your welding and strengthening, in fact where I should have but didn't and I regret that now and always will.
Your going to need the support welding to hold a set of Quincy pipes (single 4 or coupled duals) and filler blocks due to their weight loading and extra vibration they will cause. The sound oh that sound of a Merc 4 banger roaring off at some event will vie with the attention given to some V-8 Cosworth with racing pipes!!
I think I mentioned that these Quincy type pipes sets, the same ones fit Mark40s, Mark50s and KG9s and have been sold recently on eBay as well privately on North American boards like hydroracernet and BRF here and want adds can be posted for the same exhaust systems. Most sell for $200-$300 complete but have seen some more more (chromed ones) and some for a bit less too. They are steel and welded systems with aluminum filler blocks. If I see some I will post you a link.
You don't need a carb change to use open pipes but you will have to turn out the high speed needle to richen the air/fuel through the carb and cut back timing to .275 inches before top dead center as maximum timing advance setting.
When it comes to spark plugs to use with engine with pipes or without pipes the best would be Champion J4J (earlier) or their equivilent like Champion J4C (late model) of their equivilent in NGK or Bosch etc. They are 3/8th inch thread reach sparkplugs. Mixture oil /gas rated at TCW3 is best at 12 to 1. using regular grade gasoline. Do not let anyone talk to you about lesser contents of oil in the gas mix. Mercs love mixes from 10 to 1, 11 to 1 and 12 to 1. The engine was designed around lower octane regular fuels back then so using top grade or racing gas or aviation gas is not necessary and won't change performance. Champion J6J, J6C or their equivilents in other spark plug makes were used in these engines for cruising applications as opposed to racing applications and will not foul easy being a higher heat range but in racing J4Js or equivilent are best for racing.
Your heading for making one neat engine! Leaving that hack job recoil off and using the rope basket starter up there looks and works perfectly fine. If the flywheel is unaltered in diameter, thickness and weight leaving it that way is fine. If it has been reduced to the diameter of the rope plate it would make for an engine that spins up real quick too though it does not affect the overall sound level if on pipes it all just a lot more sporting! Start a Merc 40H anywhere on pipes at some motor sports event will get you immediate attention to your raceboat rig!
Keep on doing it and post a progress report. Need me to find you something for this engine on this side of the pond email me at - catwerx@hotmail.com
Cheers :)
Mercury and other outboard (OMC) Racing Sounds on Youtube
Steve:
If you want to hear the racing exhaust sounds of Mercury 4 bangers with pipes get on to Youtube and type in to search - "d mod hydro" and leading the pack is a single run by unkiemotorhead at a body of water called saltsprings. Your Merc 40H with pipes would sound very very similar to that!! Grinnnnnnnnnn!!
Off shoots from that Youtube search will also tage NBRA D-mod hydros racing as well as Super E s racing and so on. One thing really missing is a good sound and movie clip with a Quincy Flathhead 2, 4 or 6 cylinder with their 2, 4 or 6 open pipe stacks. When I was a teenager Alky Quincy-Mecs Deflector / Crossflows and Quincy Flathead loop engines made their distinct music my DSH powered KG9 would not until the exhausts were opened up. Those sounds are sweet music to a outboard racer's ears!