Trim And Prop

[JLamb]

Many questions, I'm kinda new so please be kind:
1982 Chrysler 85 hp (858h2f) 15' Galaxie Tri-hull
1.) What is the function of the reverse cone shaped part just behind the prop? It has broken out aroungd the shaft and is flopping so I need to replace it...
2.) What if any issues are there from running without the prop nut - the cone shaped peice at the very end of the shaft?
3.) The motor ID plate says 85 Hp @ 5100 RPM - the boat runs very close to 5100 RPM @ WOT - this is good - right?
4.) What is the point of the power trim for and how do you properly set it? Adjustments make little to no difference up to the point where the prop breaks out of the water. Is this because the boat is so small? Or do I not understand what I am trying to do here?
5.) The throttle (cable type) has a large dead zone near center and must be pushed past horizontal to get full speed - I assume I can adjust this? Any tips or tricks?
6.) The fuel guage does not work - anyone have a schematic? I assume it is just two leads to the sender and a power lead - ho do I tell which are which on the guage - it isn't marked (a chrysler guage).
7.) The boat turn MUCH better to the starboard side than to the port - release the wheel and it goes right in a hurry. Steering cabels well lubed, no binding. and ideas?

 

[Frank Acampora]

Re: Trim And Prop

When Chrysler first started using the one piece lower unit, The midleg was one inch shorter than the old style--still is. The engines sat too high on the transom and with a plain tapered spacer to match the tailcone taper, the props cavitated like crazy. So, Chrysler made the black plastic "anti-cavitation washer." It works--I don't know why, but it works.

On a small boat like yours, you may not actually need it--It's going to be expensive-- but if you do not use it, you need to put a spacer about 3/16 thick between the prop and the nut. BTW: If only the center hole is worn, you can get an extra thick stainless fender washer the size of the inside of the flare washer then drill it to the thread diameter. It will locate the plastic piece quite nicely.

The engine will run quite happily without the tailcone.

5100 is right in the power range of 5000 to 5500--good.

Power trim might not appear to be doing anything and with an 85 on a boat that small, best setting might be at maximum trim just before the prop starts to cavitate. Try this: go to wide open throttle with power trim tucked all the way in. Then once you have acheived maximum speed trim out and watch your tack and speedo. I'm sure you will see both rise as trim is fed in. Then at some point, prop will start to cavitate and speed will drop again. Tap the trim switch down until cavitation stops. This setting will cavitate in turns, so when you turn the boat you must either slow down some or trim in some. You trim all the way in to drop the bow of the boat and get it on plane faster. This is used to pull skiers out of the water.

Your control is working properly and there is no major adjustment for the cables. If you feel like it, you can remove the control box and check to see that the threaded ends of the cables are centered in the fittings. But, even adjusting these will not change throw too much.

The exhaust snout has two bolts holding it and they both ride in slots so you can adjust the angle of the snout to compensate for engine torque. If the boat turns to the right, it means the back of the engine is turning to the right. Thus, adjust the snout angled to the right at the back so the force of the water coming off the prop will tend to center the engine.

BE AWARE: This setting will only be good for a narrow speed range and a specific trim setting. Tilting the engine in usually makes it steer heavy and off to one side. Set the snout for the cruise speed at which you normally run.

 

[JLamb]

Re: Trim And Prop

Thanks for the help. I appreciate the time.