MarTay6

I'm just getting back into boating after about a 35 year hiatus... when I was running boats back then, the hot ticket was exhaust throttles- rotary valve drums in the exhaust to slow the engine down by blocking the exhaust... with instant throttle response when it was opened back up. I don't see these any more... is it because carb's have improved enough to make them unnecessary??? Or the larger carbs aren't needed??? Just curious!
Wes

R.J. West

Theres been a few changes since you've been gone. You may still find prather and k&b exhaust throttles on ebay.

Ron Olson

My Feedback: (1)

Yes, you have been gone for a while!
Exhaust throttles are hard for a lot of people to tune, a carb is much simpler as nitro engines can be a pain as it is with just the carbs.
Throttle response time isn't really a big deal when you're running wide open most of the time.
35 years is a while as that's about the time that I started. A LOT has changed since then. When I got started we only had stick radios and the wheel radios were just coming out. No electronic speed controls as we had rheostats with an arm on a servo to control the speed on electric vehicles like what we had in slot cars. We thought that no one would ever hit the magic 100 MPH barrier, now we've got boaters shooting for the 150 mark.
To paraphrase the old commercial, we've come a long way baby!

gonggongboy

So are the exhaust throttles a NONO. And do they hurt the performance of the motor....

Ron Olson

My Feedback: (1)

I wouldn't say that they're a no-no as now it's more of a west coast thing, you just don't see them too often east of the Mississippi any more.
In days of yore, some of the engines used both carbs and exhaust throttles. There was linkage running off hte carb to a plate that rotated as the throttle opened. Us old geezers may remember the K&B Torpedo .40's.
Joe Monohan at 707 Specialties may still be selling exhuast throttles for the K&B outboards. If you've seen the K&B SS gold head 3.5 OB, the exhaust flange going to the cannister muffler was an old part brought back from the dead as where the plug is located originally had an exhaust throttle butterfly in there. The cannister muffler was also from an old inboard.

gonggongboy

Im asking because i found a picco 80 that has an ehaust throttle and wondering if it was a good idea...

kawjs550sx

I'm running a K&B 3.5 exhaust throttle engine with the stock barrel exhaust and it works great. As previously stated, it is a little more difficult to dial up to top speed. But for sport fun in my mono, it works great and is plenty fast.

boatnut

Hey Ron, I am one of the older geezers, I started RC with push
button pulse transmiter with rubber band escapments.
Talk abouty tricky control.

Ron Olson

My Feedback: (1)

Well, ya got me there! I got into it back in the early `70's.

x33racer

I used throttle exhausts in all my boats (quite a while ago). Used them on a couple veco 19's and a couple torpedo 40's. All the loop scavenged motors seem to perform a little better with them over a regular RC carb. We had about 5 different diameter intakes we would use for various altitudes.
I've noticed the performance advantage with the throttle exhaust seemed to be mute when the newer ported motors came on the scene.

bigstang

well i just found one on ebay lol i thought it looked weird

http://cgi.ebay.com/K-B-7-5cc-45-MAR...item335cc0c206

Hydro Junkie

That is a carborated engine, not an exhaust throttle. Here's the same model in a boat of mine

bigstang

lol my bad its kinda like back wards lol sorry

NitroheadUSA-1

Here you go.