Omc 140hp cross flow

[FMP]

Probably running strong by now.

[Jimmybar]

Probably running strong by now.

one more trip with old motor ....then ,THE TRANSPLANT

[powerabout]

Attachment 407204Attachment 407205Ok , 5 mins on the die grinder, piston on the right is the v4 slotted version v6 version has 3 slots, piston on the left is mid range power mod ;note the piston at TDC gives max, port opening on tdc charge. this will go into the turbojet project,,,thats not the finished port job , might post that latter,

I forgot to ask if you have (for the 4 port engine Stock/KR/CCC) cut the middle bridge out to make a large port, how is the result same for the exhaust, anyone?

[Jimmybar]

g'day all ,well its been a while , drought, bushfires ,covid, now floods , however the upside of covid self isolation is time in the workshop , LETS GO, there's more

[LakeFever]

Just bought a stock 140, we'll see if I do some of this over time. Not in any rush got plenty to do first.

[Jimmybar]

Just a footnote to those who are new , this mod 3,, a experimental mod based on a Scott motor cycle mod in 1905, which was very successful to 1930 , performed well in racing , too well ,it was banned from racing against the same class of four strokes because of the "Unfair performance advantage ", the engine was a crossflow two stroke with a strong midrange power curve , peak revs were 5500 rpm , this is what got me in , so just because we can , I tried to replicate the same theory of tune to the omc 1600 FT engine and to my surprise it did the same to this engine , now done a dozen tanks of fuel , the engine is a stump puller , awesome hole shot fast ecceleration , but don't get to excited about revs , 5700 rpm , was hoping for a bit more , but there safe rpm , this mod is specific, pulling tubes or skiers , yes , punching heavy boats out of the hole , yes uses less fuel at cruise , definitely, high speed performance " No, " , just want be clear on that , this is a truck engine style mod , in my case the outstanding feature of this mod is fuel efficiency, I do the same trip up river , and I'm using less fuel , the saving is coming from quicker hole shot , less throttle to hold 5400 rpm , well its been a great ride , many thanks to those on line for your generous help and knowledge , also to those who have supplied some ungettable bits , this is boating , BIG THANKS , Jimmy

[FMP]

Nice !

[Schramer]

g'day all ,well its been a while , drought, bushfires ,covid, now floods , however the upside of covid self isolation is time in the workshop , LETS GO, there's more

Sweet velocity stacks!! I have an update on "my" project I have been speaking with you over the last yr or so...…email me or give me a call in the next few weeks so I can go over the details with ya.

[Jimmybar]

Can do , my turn to call , and the stacks ,ohhhyeah,,, there music to my ears at 5500 , the induction roar ,,makes the hair stand up on the back of the neck ,now that's boating , never did find the manufacturer , they compliment the 1 3/8 " carbs , for sure , be intouch Chad ,,,cheers James

[powerabout]

Can do , my turn to call , and the stacks ,ohhhyeah,,, there music to my ears at 5500 , the induction roar ,,makes the hair stand up on the back of the neck ,now that's boating , never did find the manufacturer , they compliment the 1 3/8 " carbs , for sure , be intouch Chad ,,,cheers James

I think Land n Sea had ones that looked like that

[Jimmybar]

couple engine bay shots , any feedback welcome electric fuel pump makes start and prime easy, not that happy with fuel pump location , might need to be lower , ignition cdi bracket turn out well, older block pattern with new ignition bits ,

[Jimmybar]

I think Land n Sea had ones that looked like that

Your right ,,,"Bob's machine shop ",

[powerabout]

you gotta get that exhaust sorted to on a jet to get the best from it.

[Jimmybar]

[QUOTE=powerabout;3228078]you gotta get that exhaust sorted to on a jet to get the best from it.[/QUOTE , yes , but how,,,this unit is 25 years old, jet units have evolved a lot , and to answer the question ,most have external exhaust systems with ecu controlling the amount of water introduced into the exhaust stream , to control pulse wave , top idea , best I can do is play with water into exhaust stream , but to change the gas flow circuit , hhmmm, big job , i did deburr and streamline the tract leading to the megaphone oulet in the exhaust muffler, giving a nice clean crisp note , though acceleration to 5700 rpm ,, exhaust gas circuit on a turbojet drive ,could have been a lot better ,this is evident in modern units having external water tune exhaust systems , like seedoo , you could go online and have a look for me , maybe different eyes see different things ,

[FMP]

Can't recall what " bubble back" is on this motor , if it's the same then ties in to that snake. Would you have enough space for a different exit from the lower bubble to a megaphone type tuner of stock length angled down and away to the stern? Then if space permits build a box around that with a clean exit out the lower transom. All sealed tight with a wet to dry water regulator washing the tuner if you like. So a welded aluminum box containing the tuner with through transom exit down low. A suitable exit transition that would flex with the powerhead movement of the box but stay fixed to the through transom. Like a 3" through hull. Just spit balling.