Crossflow 235 up and running, impressions and questions...

[Steve2ManyBoats]

With the help of board members here, I got a 79 235 Crossflow up and running. Got the low hour, fresh water motor DOA with no spark and swapped in a later year ignition system (35 amp alt and single box ignition). Easy swap wtih very few issues. Motor went on a 20' Sea Ox center console with T-top. Very strong, heavy boat that my V-4 Crossflow 140 huffed and puffed to push.

First impressions about the 235 (realizing I'm a lifelong Merc guy):

1. Idle is unbelieveably smooth - Way smoother than the V-4, any V-6 Merc I've seen. I've been told that Crossflow V-6's don't idle well, but this one is really nice. Trolled for stripers with it for a couple of hours at 650 RPM and it never missed a beat.

2. Fuel consumption is very good - It's on a par with the 140 it replaced. I'd also been told about the "2 thirsty 5's", but this one is pretty easy on fuel.

3. Motor absolutely does not like to start when partly tilted - I live on shallow water so the motor often has to be started partly tilted. This has been no problem for any Merc's I have or for the V-4 Crossflow. But the V-6 Crossflow is a PITA to get going. (Question- is this normal?)

4. What should this motor turn? I'm turning about 5,000 with a 20" Raker. Top end is pretty decent - though my GPS took a dump and I have no numbers. Boat went 35 wtih the 140 and it's now going way faster - I'm guessing about 48. However, with the 20" Raker, the boat still takes a while to get on plane. If I go full throttle, the prop blows out before the boat planes and I have to feather the throttle. Once on plane, it moves along just fine and I can use quite a bit of trim to air the boat out a bit (or about as aired out as a heavy fishing boat can get). Note the motor is set up fishing style - cav plate even with the bottom. (Question - should I be using less pitch?)

5. Oh, and the motor won't shut off - Just started this yesterday. Key off/motor won't shut off. I assume this is a short to ground ignition and that my key switch is bad. Is this likely the problem? Is this a common problem?

Thanks to all for the very helpful advice. This is one of the best boards around.

Steve2ManyBoats

[EMDSAPMGR]

Your engine was factory rated to turn between 5250 and 5750. You need to go down to an 18 raker (NLA) or to a 17. At 5000, you are lugging the engine. The lower pitch will really help with the holeshot. With a cupped prop, you could raise the engine one hole on the transom and get closer to 5500-5600 . It is possible that you have a bad key switch. The switch puts ground to the packs when turned to off. That ground signal is sent throught the black wire with the yellow tracer. Happened to me once when I put a different (used-6200 limit) power pack on one side. Ran fine, but would keep running after I turned the key off. I think the pack had a bad circuit or was not compatible with the other. Replaced it and the engine shut off fine. Does your engine not start when warm, or just when it is cold. You will find the carbs leak somewhat when tilted, causing the oil/gas mixture to accumulate in the bottom of the airbox. It then gets sucked into the bottom cylinder through the drain hose and may over-choke it till the engine is running and it clears out. Also, the top carb has probably has no choke plate on the shaft, so it does not help choke the engine at all when starting.

[Steve2ManyBoats]

Thanks for the reply. Looks like I need less prop. I had originally thought I needed a 22 or 20 so I got a close out on two older, unused Rakers. Both seem to be too much prop for this rig. Really like Rakers but since the 18 is NLA, how about a 19 Viper? Rakers are pretty fast, I've found. How good are Vipers? The Viper looks like it has less blade area and less rake. Does that mean that a Viper would spin up higher than a Raker, pitch for pitch? If so, do you think that going from a 20 Raker to a 19 Viper could get me the 400 to 500 RPM @ WOT I seem to need?

Another odd thing I noted about the 235. Almost all the exhaust gas goes underwater even at idle. On my V4 crossflow and my V6 and I6 Mercs, no exhaust goes under water at idle. On my 235, lots of bubbling. Is this normal for this motor?

The starting problem is pretty much any time the motor is tilted more than a normal running angle, hot or cold. I guess that's just the way it's going to be.

Still chasing down the electrical problem.

Thanks again..Steve.

[EMDSAPMGR]

I think I saw an 18 raker on ebay last week. They are still around and are good props. Each prop pitch you change will make about 150 rpm difference-when you get props close to the the right pitch. (this formula is way off when you are off 4 to 5 pitch.) I've not run a viper. Most flatback crossflows dump water and exhaust out the two exhaust relief holes at the top of the midsection. The bubble back V6 engines (like yours) have a different exhaust adapter ontop of the midsection, so they don't as much. You might want to consider changing your carbs to a later year crossflow. The newer ones have nipples and a fuel primer system. The primer forces fuel through the nipple, down the throats of the carbs. No more choke butterfly. Pretty slick.

[Steve2ManyBoats]

Thanks for the continued posts. Much appreciated.

I isolated my ignition problem. The deadman switch works but the ignition switch does not turn off the motor = bad switch.

Regarding props, what do you think of a high 5? There is an 18 pitch High 5 on ebay now. I assume that I could drill out part of the splines in the hub to run it on my crossflow. I'd heard that High 5's have a really good holeshot, good in rough water, lotsa bow lift and decent top end. Think it might work for me?

Thanks again...Steve.