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OMC 23 vs Merc 30

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chip1955

New member
"I recently retired my 1982 16

"I recently retired my 1982 16 ft Glastron that had a Merc 3.0 in it and got a 1989 16 ft Starcraft that is equipped with the OMC 2.3.
I wonder if anyone can tell me if what I am observing is normal or if my OMC 2.3 is needing some adjustment. When I give it full throttle,( even when it is warmed up) it goes to about 3000 rpm and acts 'boggy' and slowly begins build rpms and to plane eventualy running pretty smooth and topping out at about 35 mph at about 4500 RPM. The other day with just the 2 of us in the boat and my wife driving and my 280 pound carcus sitting in the far back, it would not plane at all until I moved forward. How many RPM should it be running at wide open throttle? Somewhere I got the idea this engine would wind up to 5000 rpm or better? I wonder if this is the best it will do, if it will pull a skier out of the water before he gets too tired hanging on?
The Merc 3.0 I had in the other boat seems like it had tons more power and planed almost immediately and could pull 2 skiers out of the water easily.
I am know there is significant difference in the displacement of the two engines so am just wondering if mine is working about as well as I should expect of if I should be looking at trying to get it to run better?
Thanks for any feed back!"
 
That engine should be around 5

That engine should be around 5200-5600 at WOT. The fact that you aren't reaching those RPM's and the boggy feel could just be an over propping issue. What size pitch is the prop? You may need to come down a couple of inces
 
"Bob,
Thanks for the reply an

"Bob,
Thanks for the reply and suggestion. I am not too bad with engines in general but not a very expereinced boater. If prop pitch on a boat corosponds to gearing in a truck? I can see that 'too much prop' could be lugging the engine down and not allowing it to wind up. I assumed the prop that came on it was the proper one. This may be a dumb question- how do I determine what pitch I have? I really appreciate this forum and thank you for your help.
Chip"
 
"Chip...have a look on the pro

"Chip...have a look on the prop itself, either on the hub or even on the center where the blades attach, you may find a PN or better yet the size for example 13 1/2 X 17, the first number is the diameter of the prop and the 2nd is the pitch, the higher it is the bigger bite it takes, if yours is high like a 17 or 19 you may need to come down. As a rule of thumb an inch of pitch will change your RPMs by 150-200."
 
"Bob and group,
The boat is o

"Bob and group,
The boat is on a lift and the water is still way too cold for my liking to wade out there chest deep to check out the prop so I'll try to get some youngster to do that for me. On another matter, I wonder if the automatic choke is opening up all the way. Does anyone have a diagram or picture of the linkage and arrangement of the springs on this carb? This carb is a 2 bbl with an electric auto choke located low on the carb. I see 3 screws that hold the large round cover on the choke and what looks like calibration notches. If the springs are all there and hooked up right, I wonder if the auto choke needs loosened up and turned a bit to make sure it opens all the way? What do you think?
Thanks, God bless,
Chip"
 
"Before you go playing with th

"Before you go playing with the choke, wait until you run it next time and just take the flame arrestor off and look to see if the plate is fully opened."
 
"yes sir. wise advice. <[img]"

"yes sir. wise advice.
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"
 
"Sorry...didn't mean to co

"Sorry...didn't mean to come across that way, it's just that I know some chokes can be very tempermental so no point in looking for trouble if none exists or worse yet creating some were there wasn't any before.

Now about this being a chicken s&*t about going in the water to check the prop???? Real men don't care what the temp is
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"
 
"I wrote a responce and though

"I wrote a responce and thought I posted it but didn't see it come up on the board so if the first one shows up, this one is redundant.

Bob- no offense taken. I did check the choke plate position on the warmed up engine after a fast cruise. It was not quite 100% open and felt like there was not enough pressure on it to open it all the way and hold it open. I am a cold water wuss- guilty as charged- but I did manage to check out the prop by running her up on the beach and only having to wade out knee deep. It is 13 1/4" X 17 Pitch. Does that seem right for a 16' boat with the 2.3? I also want to check out the fuel filter. Any idea what kind of filter it would be and where it might be located on the Ford 2.3?
Between the prop, choke and possibly the fuel filter, I'd like to eliminate whatever is robbing this engine of it's top end performance.
I really appreciate this disscussion group!"
 
"Your 2.3 should have a water

"Your 2.3 should have a water fuel separator like in the pic below (item 33), it's a spin canister very similar to an oil filter. I don't believe there is a secondary one at the carb where the fuel line attaches?
For the prop 17 pitch almost sounds little too high to me but even going down to a 15 would at best give you another 400 RPM. If you can get your hands on a 15 or even 13 to try that would be good but I wouldn't go and buy another prop until your sure the engine is working optimum.
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Chip I have the 2.3 engine and

Chip I have the 2.3 engine and it has the filter in the carb (#ff100). I also have the spin on fuel filter.The prop I have is 133/4 X15 13 teeth. Kevin
 
"Thanks Bob and Kevin,
I foun

"Thanks Bob and Kevin,
I found the canister and a little sintered bronze filter in the carb fuel line inlet.
The bronze one looks clean but seems to have a lot of resistance to blowing through it. I wonder if that is normal or if it is clogged finely with something I can't see. Also, should there be power to the electric choke with the ignition key turned on but the engine not running? I did this and expected to feel the choke coil chamber heating up but it did not heat up so I put a volt meter on the wire and there is no current there.
Kevin, how big is your boat and what kind of RPM 's do you get at WOT and what speed does it reach with the 15 pitch prop?
Thanks a heap for all the help."
 
"For the choke, it gets it&#39

"For the choke, it gets it's feed off the alt so pretty sure the engine has to be running."
 
"chip,I'll have to get bac

"chip,I'll have to get back to you on the rpm and speed. I just put it in the water and don't remember from last year. My boat is a 17' chris craft.Kevin"
 
"Thanks Kevin,
I changed both

"Thanks Kevin,
I changed both fuel filters and adjusted the automatic choke to open and stay open and these things helped so now it runs just shy of 5000 RMP WOT now. It really helped on the low end for power and the boat planes much more quickly and cleanly. The little bronze or brass carb inlet filter is tricky- it did not look bad at all but was pretty restricted compared to the new one.
I am thinking if i drop to a 15 pitch prop,
I would get about all the performance I can expect out of this engine and it will not be too bad.
Thanks a lot Bob for all your patient help and you were right about the power to the auto choke only being there when the engine is actually running."
 
"Good stuff Chip, sounds like

"Good stuff Chip, sounds like you are almost there, let us know if you do change props what it does for your performance, I would expect a better hole shot, higher RPM's at WOT but you may drop a bit of top end speed, just like everything else in life, props are a compromise!"
 
"chip also, my carb does'n

"chip also, my carb does'nt have a high idel. You have to raise the rpms up when you start it.I don't know if your is the same.Kevin"
 
"thanks kevin, when i first go

"thanks kevin, when i first got this boat, I found out the hard way after running the battery down twice that it has the 'ESA feature' i think it is called so that it can't cold start with the throttle/shifter in neutral. I have to pull the lever 'out' and then it acts like a stand alone throttle for a cold start and fast idle. I was used to the merc system and baffled for a while."
 
"chip, The boat will rub wot a

"chip, The boat will rub wot at 4400 rpm's and 31 mph (reading from gps). It may do better if I did'nt have 15 gal of gas and a case of beer."
 
"Thanks Kevin, That's abou

"Thanks Kevin, That's about what mine was running with the 17 pitch prop. Does it seem to take a while to get the boat up and plane and can you pull a skier?
I bought a composite or 'plastic' 4 blade 15 pitch prop and tried it out this weekend. It helped getting the boat to plane quicker and now she runs about 5200 RPM WOT at little over 30 MPH.
I am thinking this is about as good as it is going to get with this boat/engine. This little engine really only seems to come alive at 4000 RPM and above and it seems wrong to leave it screaming away but between 4000 and 5200 RPM is where the sweet spot seems to be on the power curve."
 
"Chip, when I first got the bo

"Chip, when I first got the boat (used) It tacked out at 6000-7000. The previous owner was using the wrong prop to get the hole shot to get a skier right up.This is what I was told by the prop guy. After I changed the prop to the one I have now it was slow getting on plane. I installed a plastic fin on the outdrive and that solved the problem.Yes, I can pull a skier. Mine seems to purr about 3400-3600 rpms."
 
"thanks for the info Kevin. I

"thanks for the info Kevin. I am pretty happy with my boat now. Between changing the fuel filters, choke setting and prop and running out all the old gas and running now on fresh gas, it runs pretty good now. I appreciate all the help and feed back from you and Bob."
 
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