1988 V20 with 225 Honda

Finally got out fishing Saturday. The gulf was relatively calm. Had 4 people in the boat. Two sat in front of the center console on a cooler seat (315 and 240 pounds). Ron and I sat in the back (160 and 215 pounds). This was the first time I took the boat out since I remounted the motor on the transom – raised it 2 inches. Full throttle results: 5400 rmp, 41 mph, 2.5 miles per gallon. Caught 2 keeper grouper, some nice Spanish and 3 cobia (all short). Had a great time.
 
Jackman, was that 5400 trimmed out, neutral trim, or trimmed down/under? Those honda's should be propped to turn a little higher. You might see more speed / rpm's trimmed higher.

Airslot
 
Went out fishing Sunday. Had Bobby up front (240 lbs), and Ron and I in the back again (160 and 215). Fairly calm coming in. WOT - 5400 rmp, 43mph, 2.5 mpg - motor trimmed up.
Are you suggesting I get a different prop? The engine should max out at 6200 rpms - I don't get any where near there. I am open for suggestions. Maybe a 15" at 15 pitch?
Help
Caught an assortment for fish - 54" King mackerel, 36" cobia, 24" red, lots of Spanish, and misc others. Had a great time.
 
Jackman, I'm at a loss, it just doesn't make sense. I trust your Speed numbers are GPS? 5400 RPM's spinning a 17" pitch prop through the 1.86 : 1 gears gives that 41 mph number on my boat. I still stand by what I said earlier, that motor should be able to spin 21p easy. The only other thing that I can think of is the throttle hitting the dash. I have a local buddy with a 150 honda on his V-20 fisherman and he's turning a 17'p ss prop to 6100 rpm. The Honda's are great motors, no doubt. As for your 2.5 MPG number, thats not bad at WOT for a 225. What does she cruise at? Got any numbers around 4000 rpm's?

Airslot
 
As I remember, at 4000 rpm, she does 30 mph. How do you define cruising speed? I usually go as fast as I can go - depending on conditions.
Speed is by GPS.
I agree - it just doesn't make sense. I was thinking about taking the rig to the scales, and weighing it - just to see what it weighs.
I just have 100 hours on the motor - it is ready for a checkup. Is there any test that the dealer can perform to see if everything is right with it? Is there anything I can do? Maybe check compression or something? I still can not verify that the throttle plate is wide open - don't know what to take off the motor to see inside the throttle body.
 
They can hook you up to the computer at the shop when you go for your 100 hour service. They should be able to tell you if all sensors are funtioning and how much time is spent in each rpm range. As far as determining if you are reaching WOT, try this. Take the cowling off in the driveway. Find where the throttle cable attactches to the linkage on the motor. Advance the throttle to WOT. Make a mark where the linkage is at this point. Return the throttle to neatral. Now, remove the throttle cable from the linkage and rotate the linage by hand. If it turns further by hand, you found your problem. You should be able to do this pretty easy in a hlf hour or less. Keep us in the loop.

Airslot
 
I checked out the throttle today. Removed the cowl and had a friend move the throttle level on the center console. I observed the action at the throttle body near the end of the engine. With the throttle pushed to wide open (at the center console), the lever on the throttle body was bottoming out on the throttle body stop. This verified to me that the throttle movement could go no further and should be wide open.
The dealer I go to here in Florida is a very small one. They do not have a computer that hooks up to the motor. The 100 hour check is changing oil and lower unit fluid and stuff like that.
Do you think I should find a larger dealer that has more equipment?
 
I have no idea - right now, anything is possible. I'll go to the weight station and "GIT 'R DONE".
Just had another thought. I have a hell of a time getting the boat all the way up on the trailer.
I back the trailer down into the water and position it so the fenders are just above the water. Then I drive the boat onto the trailer. Once it stops, I have my buddy see if it is far enought up on the trailer - it never is and he signals to me to come forward a foot and a hlf or so. I rev the engine - the boat goes forward some - then won't go any further (and I have the engine really revved up. I have to have him back up the trailer (slowly) - at the same time, I rev the engine and get it further up on the trailer. This process is repeated until my buddy lets me know that the boat hit the front roller. He then pulls the unit out of the water. Upon checking everything (on shore), the boat is 2" away from the front roller. We try and crank it up - it is a ball busting job - that boat just does not want to move on the trailer !!! Just can't get it cranked up all the way to the roller. I thought maybe I had to spray some sort of lubricant on the 2 sliders. They look like 2x6's with a carpet covering.
What happens is when the rig is pulled out of the water, the boat settles on the trailer, and comes to rest 2" from the front roller (which it was hitting before the boat was pulled out).
I will persue the boat being TOO HEAVY aspect of my problem.
thanks God.
 
the back of ur boat is floating in water and when you pull out it changes the yaw of ur boat. as the stern goes down, the bow comes up. if you cant hop on the trailer further out the water you should raise the bunks in the rear, or lower the nose roller. wich ever is easier on ur rig. also, are you absolutely positive you are reading mph and not knots? the throttle stop on the motor you were talkin bout, is it adjustable? ur second trip was 315 pounds lighter, same rpm, gained 2 mph. sounds like ur not at wide open throttle. and with only 100 hours on that motor, should you be?
 
How's she run, smooth or reall smoooth? Any chance she's only firing on 5 holes? Sounds to me like its time to see the tech.

Airslot
 
just a thought here and maybe I'm reachin out a bit,but, in addition to all other possible factors that are making the boat porpoise up and down, not reaching wot rpm, what appears to be low top end [43-44mph w/ a225???] could the t-top be pitched in the wrong direction???? Meaning is it catchin to much air and acting sorta like a parachute??? T-top, lotsa fuel[the tank is kinda aft,isn't it?] a HEAVY motor.....all that is certainly not any help if your looking to keep the bow down. Bottom line is that 225 should get you a least 50-55mph and about 900 more rpms. Airslot brings up a good point as well, I think it may be hard to tell if its not firing on all six, not being to familiar w/ the motor,it may be possible to overlook ???
 
Thanks for your comments!
I am going to take the boat to the weigh station today. Just had the 100 hour checkup done on the engine. The mech said it was fine. It's a small dealership, and they don't have any equipment that hooks up to the Hondas to check whatever.
He also checked for full throttle and said it was wide open when the throttle lever (on the center console) was pushed all the way forward. The WOT stop on the throttle body is NOT adjustable - there is just a part on the TB that sticks out, and the rotating mechanism just hits it.
Yes, I am sure the speed is in MPH - I have a speedometer on the console and it reads about the same as the GPS.
I'll see if I can figure out how to disable one cylinder at a time.
The motor starts right up and runs very smoothly (at all speeds).
The mech said he thought it might be the hull??
Will report more after the weigh-in.
 
If you don't feel a miss at idle to over 5k rpm, you don't have a miss.  If you're still running a 17" pitch prop on a 225 on a 20' boat, I still feel that's your problem.  The previous owner may have been happy with 42 mph. I just repowered with another 150 hp with a 17" four blade prop and I hit 44.7 mph by gps.  It would be faster by about 2 mph if it was a three blade prop.  As mentioned before, my prop came off my 225 hp that was installed on a 97 sea ray laguna 24' boat.  It was alot heavier than my V20 and it ran at 47 mph.  On the 150 hp I hit 5500 rpm which is the max for my engine.  If you haven't yet, I'd talk to a prop shop before I'd tear into other things.  Do a Yahoo search for honda outboard motor test and click on fiberglass, 225 hp and the lowest pitched prop on a 20' boat was 23 and most with a 25" pitch. Some are go fast boats, but look at the pitchs on the 23's. They aren't 17" props. Just my $.02.
 
Just got back from the weigh station. Put the trailer wheels on one part and the front crank wheel on another slab.
Here's what I got:
460 lbs one the front and 4360 on the axel. Total 4820 lbs.
Engine - 610; Ttop & box 130; gas 60 gals @ 6 lbs per = 360; misc gear ~ 200; 2001 galvanized single axel trailer ~ 700. 2000 total lbs (excluding the boat). The boat must weigh ~ 2820 lbs.
 
Even if he estimated 300lbs. under, he's still 500 lbs. more than it should be??? Sounds as if the engine is running right, what else could it be besides extra weight?
 
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