3.5 ops questions.

tmunn · Sep 9, 2007

I was dilaing on my 20 mono that i just installed a 3.5 ops speed .

I was messing with the needle and it seemed that it was rich on the bench so i launched it.

It kept pulling out the whole element in the plugs so i kept going richer.On the last try I noticed the needle had broken off flush with the brass nut so i could not go any richer .Well i launched it again and this time something poped.

It ended up being the con rod breaking at the crank.This engine had not been used for a while but the guy I bought it from had it well oiled.

The carb on the damaged engine is the one with a brass barrel that will rotote 360 degrees if you let it.It has no LSN and uses a needle similar to the 3.5 k&B.I could cut the end of the needle taper off and use a remote needle ...

I have a NIB ops 3.5 which is similar except the new one has a turbo head and buggy carb which has a smaller bore.It does however have a screw for LSN and HSN.I can make the carb work with the use of a bell crank no problem.

I heard the turbo plugs are expensive.Could i use standard plugs in the turbo head or should i put the old head on the new engine and use standard plugs

Would the buggy carb be as good or better than the one described above ?

Would anyone have a 3.5 ops speed Con rod they would like to sell ?

Would you guys suggest making one engine out of the two and if so which would be the best way to go ?

Thanks again

Terry

Radioactive · Sep 10, 2007

Terry let me check tomorrow I may have a spare rod.

Dusty

tmunn said:
I was dilaing on my 20 mono that i just installed a 3.5 ops speed .
I was messing with the needle and it seemed that it was rich on the bench so i launched it.

It kept pulling out the whole element in the plugs so i kept going richer.On the last try I noticed the needle had broken off flush with the brass nut so i could not go any richer .Well i launched it again and this time something poped.

It ended up being the con rod breaking at the crank.This engine had not been used for a while but the guy I bought it from had it well oiled.

The carb on the damaged engine is the one with a brass barrel that will rotote 360 degrees if you let it.It has no LSN and uses a needle similar to the 3.5 k&B.I could cut the end of the needle taper off and use a remote needle ...

I have a NIB ops 3.5 which is similar except the new one has a turbo head and buggy carb which has a smaller bore.It does however have a screw for LSN and HSN.I can make the carb work with the use of a bell crank no problem.

I heard the turbo plugs are expensive.Could i use standard plugs in the turbo head or should i put the old head on the new engine and use standard plugs

Would the buggy carb be as good or better than the one described above ?

Would anyone have a 3.5 ops speed Con rod they would like to sell ?

Would you guys suggest making one engine out of the two and if so which would be the best way to go ?

Thanks again

Terry

sport hydro · Sep 10, 2007

I have 2 OPS3.5 rear exhaust motors that I run in separate seducer 29" hulls. I got rid of the turbo heads because of plug costs. The motors will run alot richer than a MAC or CMB but will run as fast. They both use the standard head which you can get from Aeromarine. I am using the slide carbs but am looking at going to O.S. carbs to get better breathing as the buggy carbs are small bore.

If anyone can recomend a part number for the right size O.S. for a 3.5, let me know.

Radioactive · Sep 10, 2007

Terry I do have a new PRP rod let me know if your interested.

Dusty

tmunn said:
I was dilaing on my 20 mono that i just installed a 3.5 ops speed .
I was messing with the needle and it seemed that it was rich on the bench so i launched it.

It kept pulling out the whole element in the plugs so i kept going richer.On the last try I noticed the needle had broken off flush with the brass nut so i could not go any richer .Well i launched it again and this time something poped.

It ended up being the con rod breaking at the crank.This engine had not been used for a while but the guy I bought it from had it well oiled.

The carb on the damaged engine is the one with a brass barrel that will rotote 360 degrees if you let it.It has no LSN and uses a needle similar to the 3.5 k&B.I could cut the end of the needle taper off and use a remote needle ...

I have a NIB ops 3.5 which is similar except the new one has a turbo head and buggy carb which has a smaller bore.It does however have a screw for LSN and HSN.I can make the carb work with the use of a bell crank no problem.

I heard the turbo plugs are expensive.Could i use standard plugs in the turbo head or should i put the old head on the new engine and use standard plugs

Would the buggy carb be as good or better than the one described above ?

Would anyone have a 3.5 ops speed Con rod they would like to sell ?

Would you guys suggest making one engine out of the two and if so which would be the best way to go ?

Thanks again

Terry