Slam your hand in the door first thing, an stay psised the rest of the day is about the only way to drive them haha

 

at 1300 rpm they sound like they are running 7500 keep it cranked up so it dont slobber all over its self they are decent on fuel but keep the ear plugs handy

 

That's one of the reasons my hearing is bad. 671 with straight pipes in an old Jimmy 9500. Between the 671 & 871 is probably a reason I have an attitude lol tired of slamming the door on my hand everyday lol. The best thing about the good ole days "is they are gone". If your 671 dont leak oil you better check it because it is probably out of oil. As said above they never quit, they may stop running but never quit being a good boat anchor.

 

Yeah, but that's not good for the door.

 

The really are quite the motor. They get a bad rap and deserve most of it, but I have never seen something that can be taken care of so poorly and just keeps running. I think we have 3 or 4 of them in different old pieces of equipment right now, and rarely have problems with them.

 

Actualy change the cam and they can run backwards.

 

6-71 are great engines, not that it matters in your case but they can be built anyway but upsidedown, left, right, standing up laying down, blower and exh on either side etc. Some of the hi-po Johnson & Towers are 485 hp single turbo engines. They are noisey but sound awesome. However if a detroits not leaking it must be out of oil. Find a reputable tech to have a look and help you out.

 

Go here www.4btswaps.com and look in the Detroit room, lots of knowledge there

 

This is the truest statement anyone could make.

If this boat has only one engine it is underpowered. The only problem with this engine is it can't be lugged, I don't think you would be able to plane this boat out enough to say it would not be lugged. If it goes short distances, trolling type fishing, etc. you would be fine. If your going to be going long distances (hours) with the engine wide open I don't think it will make it long. One thing you have to consider is the bogging down you get with these boats from climbing/busting wave(s) and sudden cutbacks with the throttle when you top waves, this puts an extreem amout of torque on a crank shaft, you just can put any engine in its place. If you replace this engine you probably would have to replace the drive also, most others will not run the RPM's the 6-71 does. If it was me, I probably would pass on this boat. You don't say the year but a 6-71 I'm willing to bet this is a 1978 or older boat. Good luck in you adventures.