Backfire/misfire thru carb

[billw]

Beno wrote:

I actually sold the turbojet longblock complete years ago. the heads went with it.. but I’m sure I can get more on Fleabay. I’ll keep an eye out for them on ebay.
I would need new head bolts and 2 new gaskets if I removed the head right?

On the fuel gauge that is great info I appreciate it. But what happened is that the gauge was working and for some reason (it’s like a 16 gallon tank) the sensor doesn’t start to read of Empty till you get to 8 gallons.. then it goes up to Full as you get to 16/16 gallons. something new every day.

I suppose it could be a very strangely-shaped tank but more likely is that somebody botched a previous attempt at sensor replacement. The senders come to fit a range of say, 6″-12″, 12″ to 24″, whatever. You have to follow a very specific procedure to modify the new sender to fit the tank. If you screw it up, it won’t work right. Like my old boss always said, “Read the destructions!”

Long live American manufacturing!

[fleetwin]

Beno wrote:

as I recall one of the cylinders went Real bad.. so it’s likely only one of the heads would have been salvaged anyway.

My experience is that permium fuel runs VERY hot.. are you sure the increase in heat is worth the increase in longevity?

Well, I’m not sure it burns hotter, but it does help with uncontrolled combustion which leads to detonation/preignition damage…You could always increase the size of the high speed jets by .002″ to combat any extra heat….But, at this point, now that it is running OK, it is best to just sell it as is….

[Beno]

That omc 140hp is out on tupper lake area this weekend with my brother and the kids.. it does run hot tho! They are stopping every so often to let it cool off.

• This reply was modified 2 years, 8 months ago by Beno.
• This reply was modified 2 years, 8 months ago by Beno.

[fleetwin]

Perhaps I missed something in one of your posts…But, how is it you are determining that the powerhead is running hot? Are you judging temp based on gage readings? If so, please know that these gages or often inaccurate and are affected by high battery voltage. Did you keep the water cooled regulator/rectifier from the original turbo jet powerhead? Or, are you using the simple rectifier only system that was on the older 140 powerhead? High battery voltage drives those gage readings up giving false readings…

[Beno]

I havent found any turbojet heads yet. So just the stock 1978 omc heads for now

My brother took the sunbird w/140hp up to Tupper Lake . He just uses a laser temperature shooter to see what temp the block is after pulling the kids around on the tube.

As far as charging… whatever the 1978 magneto puts out is what we have. All 78 on the block…

The exhaust system has a lot of rubber hose.. and you can smell its hot.

See pics

Josh is good at foul hooking smallmouth bass.

[fleetwin]

I wonder if some of the water that is supposed to escape from the top of the heads is directed toward hot spots in the exhaust….Not too familiar with the turbo jet cooling schematic… Have him check temps on top of the heads and on the exhaust manifold/cover on the back of the powerhead…

[Beno]

I think you may be right. We plan on threading some holes if we keep that powerhead in there. Im getting really good at swapping v4 powerheads so we may just put a 115 in next summer instead. Its really got more power than it needs at 140hp (and i think its bored .090 over!)

Kids are setting new altitide records om their tube.

[fleetwin]

I would leave it the way it is, but find a turbo jet cooling schematic, the drill/tap the current heads…Do you know where the water from the heads is supposed to be directed? There must be some port somewhere that is plugged off because this is missing….

[Beno]

Yes sir, I do know where it is supposed to go… the two rubber lines merge in a T then go to the Baffle – muffler affair on the starboard rear of the boat… see pic of some boston whaler with turjet.. the pink likes show water flow direction.

we plan to tap the water jacket covers on the heads.. that way we can just remove the gasket covers and not actually have to go down the whole remove the heads route. new head gaskets..etc.
the water jacket covers provide the same access to the same waterway path.

[fleetwin]

Like I said, there is not much room under those water covers for drilling/tapping

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