Engine still not performing

[louxwe]

So I am having some issues with the folks I took my engine to and wanted to see if what they are telling me is correct.

I pulled the boat last fall for shoulder surgery and left it out for several months. While it was out I had someone do some maintenance (500 hours) general checking all the gear oil, seals, tune up etc. I have a 75HP Honda BF (BF75A6), not sure of the year, but it is carbureted and the boat is a 2006 so the engine is around the same, maybe 2004. Previous to all of this it would run up to 6200 RPM but I would usually cruise at 5700-5800 and do maybe 24 knots assuming a flat day. Right before I pulled out I tried on a 4 blade prop and the RPMS and top speed dropped a bit lost a couple hundred rpm and couple knots of top speed.

Got the boat back in the water in Jan and right when I tried to drive it first it wouldn't go when I put the throttle down, it just sort of chugged and stalled. They said that they needed to adjust and balance the carburators and idle. After that it drove okay, idled much better and ran when I gave it throttle, but ever since then when I put the throttle all the way down it only goes up to barely, I mean barely hitting 5000 RPM and in perfect conditions, flat, no wind trimmed perfectly I'm getting like 19 knots. I thought maybe the throttle cable was off or something. Before I never would have to push the throttle 100% forward, would only go to about 70-80% and hit around 5800 RPM. Now I have to absolutely jam the throttle lever all the way down to the bottom and I'm barely getting 5000RPM. They took it back again and said they checked the cables and they are adjusted right and they supposedly took the carbs apart and checked and it is getting all of the fuel it is supposed to. I also changed back to the original 3 bladed prop. So now they are telling me that 5000 RPM is the max RPM that that engine should have.

Is this true, I believe the max RPM for these engines is much more like 6000... Esp since it was running fine like that before. Then he said that the engine is just way to underpowered for my boat (I have a C-Dory 22 and most folks on here have a BF90 Honda and seem to run much higher RPM and speeds) he then said I should have more like a 150 HP or more on this boat but I don't think it is even rated for engine HP that high. Then he said that he didn't know what to tell me, said it had the right fuel flow, cleaned carbs, and good compression, and it was just too old of an engine and 5000 was the best that it was gonna do.... but just six months earlier it was running way better.

I have not had the boat very long and originally just wanted to take the engine to a professional to have it run through and checked out but now ever since I got it back it has been running worse than when I took it into him. I don't really know much about outboards and really don't know what to do right now. It seems to run sluggish, and not much power at 5000 RPM... he said maybe the valves are no good or something, but I just don't know how it could have gone down that fast. I am now a couple thousand dollars into this and not sure what to do, or what else to check out or try.

I suppose I could take it to someone else but don't want to dump another several thousand into it and have them tell me the same thing.

Pretty bummed out now, just wish it was running like it was before.

Any advice on what else I could check/try out.

Thanks, Bill

[westward]

Based solely on your reporting of the conversation with your outboard mechanic, I would absolutely take it to a different mechanic. Not to besmirch this fellow, but his statements seem to indicate a lack of knowledge of your Particular boat and engine set up.

For what it’s worth, several of my worst mechanical failures have come immediately after having taken the engine or outdrive in for “routine“ service

[C-Green]

I'd call Mark at Wefrings and discuss the situation. Might be worth the tow taking it to someone who knows C-Dories and has an outstanding reputation. I suspect maybe a blackbox(computer) issue or a sensor issue. Is your mechanic Honda certified or does he work on Hondas often?

Jay

[louxwe]

I don't think he works on a lot of Hondas they don't seem as popular where I am at. NW Florida/Destin area, does anyone know any Honda specific service shops in the Destin area.... just hate to start all over with someone else and possibly have them spend more money/time working on it. Kind of a bummer.

[thataway]

Yes that is a bummer.

Mac Grove at Weffings does a lot of Honda work. He is in Apalachacola. He used to be a Honda dealer. Looks like mostly Yahama and Suzuki currently in selling.

Posner Marine in Pensacola has been a Honda Dealer for over 25 years (as long as I have been dealing with him--and that is where I buy my parts.

There are a number of things which could be causing your problem. The WOT speed is 6000 RPM. You should not be running the boat at close to WOT all of the time. The people you have dealt with don't know anything about C Dorys--if they suggest 150 HP. The boats are rated at 115 max. They were initially rated at a max of 90 HP. The flat bottom requires far less HP. (I had a 20' GradyWhite which required 225 hp for max performance...but not the c Dory!)

It could be that your rev limiter was set at 6200, but I have never run a Honda at over 6,000 RPM. You should be cruising in the high 4000 to low 5,200 RpM range with a 75, unless you have an unusually heavy boat, or the bottom has a lot of growth??? The Hondas run best with a 3 blade prop.

He tells you the valves have gone bad during the winter, and the compression is good? What are the compression numbers on each cylinder? Was a Leak down Test done?

[louxwe]

I don't remember the compression numbers but I think he said something like 128 130?? But he checked the throttle cables, and took the carbs apart, check the spark on the plugs, checked the fuel flow to the carbs and said he check the compression and said it was all within specs. Said to check anything further he would have to look into cylinders, maybe rings or something deeper inside. Not sure about rev limiter or how that would effect it... if it was at 6200 then I should be able to go up higher right. As of now I am only getting 5000 rpm with 3 blade 13.75 inch and 15 inch pitch. It seems like most folks are getting higher RPMS with the same set up. I did just clean the bottom and put new bottom paint on it so we will see if that helps but I wouldn't think that would have that much effect on RPMs, maybe end speed, but even so the bottom really wasn't that bad at all, had only been in the water 4 months.

[WeekiTiki]

Got the exact same set up

Mine has never reached 6000

Maybe 5500

Of course I have no idea what pitch prop I have either

[louxwe]

What is your speed at 5500. I went out today with him again for a test ride, downwind on a flat day and the throttle mashed all the way forward it hit 5200 and maybe 22 knots, but that's all she had... he suggested using Ring Free, I guess it is something to knock off carbon build up. Only other difference I can think of is my prior prop was 13.5 in in diameter and this one is 13.75 in in diameter both were 15 pitch. I really don't think 1/4" difference would make that much speed/rpm difference though.

[WeekiTiki]

Haven't been anywhere smooth enough lately to actually tell

Boat ran out to nearly 30 on a smooth lake...

without gear.

Honestly, if I go 20 that's fast

[starcrafttom]

stop taking it to that dealer or get the management involved. many shops will only send the motor to the guy that worked on it last instead of getting fresh eyes on it. the fact that he does not know what the motor rating is concerns me. ring free can be used in 4 stroke but its for 2 strokes so that concerns me. But to the motor. it sound like what happened to my 50hp. sounded like it ran fine but was not making full power, sluggish, etc. I tested compression but that is done with a gage when the spark plugs are pulled. But is that plug firing? Sounds simple but some people over look this because the motor runs smooth even with out the one cylinder firing. My motor had one power pack out. some people call it a igniter. One new motors there is one for each cylinder. easy to check. Just start the motor in the water or on the muffs. then pull the spark plug wire on each cylinder at a time. Pull the wire and see if it stops or misses or not. It should miss at least when you pull the plug. If it does not you have a bad plug or igniter. change the igniter from one of the other cylinder and see if it fires. You could also have on injector or carb plugged but I beat its a igniter. I was very surprised that the motor ran at 5000 rpm on only 3 cylinders for 20 miles coming back from fishing. thanks my advice.

[thataway]

[dutch123]

Well I think Bob nailed it. Some parameters that can and will have a considerable effect on the performance of your motor have changed. Go back to the same conditions with all things being equal to make a fair comparison of current performance levels as compared to previous performance levels.

[louxwe]

Well whatever these idiots who worked on my motor did, they really messed it up. I used it maybe 10 times this summer, all the time never getting enough rpm or as much speed as I should, not running great, went out today and it is just pouring fuel out somewhere around the top carburetor.

https://youtu.be/WMfCRkqiOtA

Anyone have any ideas on what could be wrong? Not taking it back to the idiots who worked on it, would like to find an authorized Honda outboard dealer/mechanic shop. Any good recommendations in the fort Walton beach, Pensacola Panama City area?

Thanks Bill

[louxwe]

Well whatever these idiots who worked on my motor did, they really messed it up. I used it maybe 10 times this summer, all the time never getting enough rpm or as much speed as I should, not running great, went out today and it is just pouring fuel out somewhere around the top carburetor.

https://youtu.be/WMfCRkqiOtA

Anyone have any ideas on what could be wrong? Not taking it back to the idiots who worked on it, would like to find an authorized Honda outboard dealer/mechanic shop. Any good recommendations in the fort Walton beach, Pensacola Panama City area?

Thanks Bill

[johnbenj]