OutdoorKing Repair Forum Forums General Discussion Forum Off Topics Race-ready Intek

Hi all. I am working on making a racer using a 17HP Intek. Can I just disconnect the governor linkage and run a throttle control straight to the butterfly or do I need to do some internal work?

I'm not clear on what the question is, aussietrev. If you connect a Bowden cable directly to the throttle butterfly, you will be able to operate the throttle like on an old carburetor-style car engine, but like on the car engine, if you open the throttle wide with insufficient load, it will either valve-bounce or blow the engine. In the case of race engines you usually stiffen the valve springs, which makes it quite sure it will blow, not valve-bounce.

Preparers of mower racing engines usually accept that they won't last long, and make a series of design changes aimed partly at increasing the output power, and partly at holding them together for the time it takes to complete a race. Then they get back on the spanners and rebuild them for the next race.

I can remember Jack Brabham being interviewed on TV, right after his engine blew in a Formula Libre Cooper mid-race at Sandown, when he was in the lead. The interviewer commiserated with him over his bad luck. Jack said it wasn't luck, he'd missed gears twice in the race, and the tell-tale on the tachometer was pegged 500 rpm above the red-line, so there was every chance it would blow, and it did.

Thanks Grumpy. I was reading an article on setting up the 6HP Chonda's as cart motors and the guy had gone to a lot of trouble to pull it apart and physically remove all the bits associated with the governor. I couldn't really understand why he had gone to that length and was wondering if it was necessary or if, as you say, simply connecting a new cable to the butterfly would do the job. I guess I will need a choke cable as well?
I had some personal dealings with Jack some years back. While he was a great driver and knew an awful lot about motors, he wasn't the decent human being a lot of people thought. Sorry to speak ill of the dead but it was a shock to find out what someone I had always admired was really like.

There are a couple of reasons to remove the crankcase governor parts. First, never include anything on a race vehicle that is not required either by the rules or by the function, because it adds weight and complexity for no advantage. Second, unless the governor arm is attached to the governor shaft and spring-loaded in the anticlockwise direction, the governor plunger is not going to be restrained by the paddle on the governor shaft, and it may fall off inside the crankcase. The plunger is usually a small moulded plastic part and if it moved around freely it might either melt onto something, or jam between a couple of moving parts (one of which might be a plastic timing gear, for example).

I think it would be unwise to try to use the coupled linkage mechanism between the throttle and choke, so you would need a separate choke control. It may not be a cable though - one of the things you should do with a race vehicle is keep it simple, because sooner or later everything breaks or falls off, so the fewer parts you have, the better. For most types of racing you warm up the engine before the event, so it is convenient to use a simple lever attached to the choke butterfly directly, with a reliable device to hold it in the wide open position. In the good old days, which I think may be still with us for some times of full-on racing, you warmed up on "soft" (or "hot") spark plugs, then installed the "hard" (or "cold") plugs just before the race. Of course you did not allow the engine to idle on the hard plugs, or you'd foul them very quickly.

I understand what you say about Jack, but the man is dead and not able to defend himself, so I'd rather not discuss it.