Outboard Not Running at Full Power | Boat Slow at Full Throttle | Boat Won’t Accelerate | Boats.net 

Heres my number one discovery for loss of full RPM and that is usually fuel starvation, or a pinhole leak in a fuel line weakening the prime. Check for a flattened bulb in case theres an obstruction or faulty check valve. Other things you mentioned are things that dont happen unless someone has changed something.

Failed to include most reasons for failure to achieve speed.

Bought a 1980 sun runner 17’ ski boat. I’m looking to increase, improve, adapt it for better results.

Well structured sir, thank you !

Think you got the pitch backwards lower pitch give you more wholeshot and acceleration with less top end higher pitch gives you slower acceleration and more speed on top end

Had the problem with my yamaha 8hp 2 stroke of not running more than about half speed only 3,000 to 4,000 rpm in water barrel in forward gear. Changed spark plugs and cleaned carb and now it hits 6250 in gear and in water barrel.

Hi John, my boat will only run at 8mph when first starting. After trolling for an hour or so it will run at normal speeds. Please help me I am at a loss for where to go to fix this problem. Thanks, Brad.

I have a evinrude etec 30 hp outboard that won’t get past half speed when turning the throttle handle all the way. Any suggestions?

Sir I have a Mercury 4 strok OBM engine,I faced the engine are not build up speed above 3000 rpm ,pls sir can u explain which defect is

Cool channel, I've been working on outboards but mainly vintage and the newest a 96 60hp with CDI. I was just asked to look at a 140hp Honda EFI. The issue is it won't start? I've read up on it so I can do a basic troubleshoot but if you have any suggestions or any of your viewers I'd appreciate it. Thanks

Just boat a boat with a Yamaha 2 stroke 70 HP (came only being able to go quarter throttle which I knew) just trying to fix it hopefully this helps. Spark plugs have a ton of carbon build up, maybe this is why? Installing new fuel pump as well.

I have a 200 Yamaha HPDI. When I got it I was getting 63 mph. Now I’m getting 50 mph. Used to it would jump on pad. Now it takes a while. Every ones in a while I’ll take off and it will get back to 63 and I’ll be excited. Go to move from my first spot and it will do it again slow to take off.

How can I check my IAC valve on my 06 25hp efi 4stroke mercury to make sure it’s bad before spending the money on a new one?

Hello, I have a 75hp Johnson engine and out of the water it accelerates excellently but when I put it in the sea it does not accelerate almost at all, it goes very slowly, I have already installed new spark plugs and a new fuel tank and hoses.

I have an older 85hp Force on 17ft ski boat. It has been running like a top until one day it became hard starting on slow (not even plaining) at top end. Had it overhauled (fuel,filters, plugs, etc.) and it now starts righf up but still no power. Mechanic said it was an ignition system (firing order) problem and not worth fixing. Cant understand how it was fine one minute and now no power. Any suggestions?

1997 30 hp johnson outboard will run top speed full throttle then just looses power, after about 10 mins. and then bog down and will only go a couple miles an hour at full throttle. already cleaned carb and new fuel lines. Im lost, any ideas

I have replaced the fuel line Assy and haven't had a chance to check to see if that's the problem yet

Like everyone else - I'm here because I cant get issue resolved. 2019 Harris Sunnier with Mercury 200HP Outboard. Purchased used last year and when we took possession of the boat it ran like a top hitting speeds of 50mph with 4-5 people on board. This season it was running rough and not going over 33mph (5000rpm) so I changed the plugs which fixed the rough running, but the boat still wont go over 33mph. If I try to trim it up even slightly it starts cavitation, so i keep it trimmed all the way down. I did change the prop hum assy this weekend to see if that fixed it and to no avail the issue still persists. NO water in the toons, cavitation if trimmed slightly, engine runs smoothly. I'm at a loss here

I need to know some idea to fixed carbrate speed

I have a Mecury 4 stroke 60HP seapro outboard, Just 20hrs . I find that some time the speed at around 5000rpm will decrease to around 4200-4500rpm.and then back to 5000rpm again without change the throttle. Do you any suggestions can give me?

My 2014 made Mercury 30HP 4 strokes EFI motor stayed at 3000rpm at full throttle, I then changed the impeller, sparks plug, motor oil, gear oil, gasoline filters, and thermostat. After the change, it only stays at 3200rpm. Could you please tell what else I should look at and what spare parts should be replaced? Thanks. Francis

i have a question sir,yamaha 300 double engine boat highspeed running time boat some unbalancing ,not stable.whats the problem.pls reply

My 87 Johnson 150 V6 bro I have no problem getting up to 40 mph, but when I push it, then it bogs down and sputters until I throttle back and it will be fine

Hello I have mercy 2004 outboard 225 when you remove oil cap on tank is the oil supposedly goes down fast or slow

Do you have a video on pulling the throttle bodies to replace the injectors? 2003 Yamaha F225TURB

I have 2011 8hp yamaha 4 stroke..starts on 1st try but when at full throttle starts backfiring......spark is good and runs great until full throttle...does anyone have a fix...

got a 73 70 horse Johnston it starts idols goes into gear and wont idle up just goes along at mile or 2 an hour

My 18ft has a Yamaha 115 on it. I can’t get past about 8.5mph at full throttle. I should be going in the very least 40 mph. Checked gas lines and changed fuel filter.

I have 1990 hydra sports 150hp v6 boat and it runs on max 12 miles per hour and some time suddenly increases its speed to fast and get it to 50mph I don't know what's the issue and some time it also doesn't start at all. What's could be the issue.....?

I have a 1993 Yamaha tiller 30ELRR I want to change over to remote shifting and throttle. Can this be done on a small budget?

New tohatsu 2023 barely used started to drop in acceleration at high rpms. I have to drop throttle to 0 and then it restarts again, any higher load like a current or waves, causes it to drop acceleration to 0. Started happening after i took it to the ocean what a shame, thousands of suggestions from everyone and none worked so far

I have a 1991 15 hp Evinrude that won’t go full throttle and the only problem is we’ve already checked everything mentioned in this video and it still won’t open up and go full throttle.

I have a 2020 mercury 115 ct outboard and it just started boging down at 3000k rpm whentryingtoplane, I cked fuel pressure, fuel, spark, spark plugs , I would like to know where is the neutral safety sw and if you have any opinion, only 77 hrs on motor.thanks!

hello, i have a 10 hp honda 4 stroke behind my 4 meter speedboat. the top speed goes about 15 km/h but I feel like it should go faster. does anyone know what could be causing this? I like to hear it!

Thank you John , this video helped me rebuild 2x225 hp Yamaha’s and they haven’t missed a beat , Just a different topic I am trying to find help on why a 2009 300 hp etech is going into limp mode on a regular basis , is there someone that you can recommend, thanks Eric .

My Yamaha 200 is fuel consumption is high what might be the possible cause sir

higher pitch means higher top speed and lower hole shot

I have a 2007 90 hp. Mercury bad idle and it surges clean carbs new filter , can bad spark plug wires cause a problem with this ,what about reeds

Why there is oil coming out the intake of my outboard (yamaha 50hp 4 stroke) help

Hi could you please help me with my question. I have a 2014 50hp Bigfoot it’s max wide open throttle is only 3400rpm, 13pitch prop with 30 hours on the motor. It’s on a 20ft pontoon boat. The manual suggests 5500-6000rpm WOT? Why can’t I achieve that. Thx.

So i have a 1998 evinrude 115hp intruder. Put on a new fuel pump, rebuilt carbs, cleaned air filter. Problem is when i give it thottle i get up on plane then it gets no gas. If i prime the ball before it stalls it will go again then stall when not priming the ball. Could it be a broken valve in the ball or clogged hose from tank to the primer ball??

I have a 2016 Mercury 4 stroke 9.9 after take off engine will not tilt at high rpm and I’m not getting 5000-6000 rpm highest it will go is 3000 rpm. Any suggestions?

I have a 2006 model... when i give it full throttle, it crawls.... there is no speed what can be the problem?

Good video thanks..

Here’s my problem…I have a 90 hp Mercury 2 stroke that I had installed on 20’ pontoon boat. From the get go it was cavitating on acceleration. The installer did not install the forward ring as he said it was optional to prevent fishing line wrapping around the shaft however the prop shop guy said it was required to prevent exhaust gas blow by, I see the point now. After installing the ring and prop it did not cavitate any longer but developed another issue of hard starting/ idling. I surmised that the water separator I installed was possibly the issue and bypassed it. That seemed to solve most of the issue but subsequent trips to the water the motor will not accelerate past 4000 rpm (will rev up when in neutral) when in forward gear. It just bogs for a while then after a few minutes it suddenly “breaks free” and goes to max rpm and speed and acceleration like it should…..The next day I was looking at motor at the house and turned the prop by hand and it was stiff (in neutral of course). I’m thinking it should be easier to rotate than that. Could it be it’s binding the hub housing until it get warmed up? Or is it carb floats sticking and then breaking free?

I have a 135 blue optimax I changed the lower unit now its peeing good hoes forward and reverse but won't go when I push down on throttle need help pleaae

I have a 08 Mercury 50hp outboard 2 stroke , I'm having problems with it not going full throttle , it idles and it doesn't run rough , what could be the problem

2010yamaha f2.5 4 stroke outboard will not peak out also engine idling is good midrange good top end a little sluggish also idle mixer screw has no effect all in or out

i have an old 8hp yamaha, it sometimes maxes on 22kph sometimes 32kph... is this because the gps on my phone is bad? or just because its an old motor? its a 2stroke from 1977

I have a 2017 115 yamaha sho. and let the boat sit up for the summer of 2021, so i take the boat out summer 2022 and its running rough engine i get the boat to the middle of the lake and i put the boat in neutral let the boat ideal for about 3-4 min. and when i went to put the boat in gear and the boat would not go into forward or reverse, Can someone please HELP...???

I have a 1980 mercury 115hp tower of power 6 cylinder when you free rev the engine it revs fine but when the boat is in the water under load full throttle is more like a tenth of what it should be I’m at a loss as to what could be wrong. Any insight would be gratefully received. Thanks

I have a 2008 yamaha 250 4 stroke wont rev after riding for about 10 miles so i turn off the motor wait a few then I start it up goes back to normal and the same process happens again. I replaced the water pump changed the oil fuel filter and spark plugs with no luck. I'm thinking it's a sensor.

No mention of the power pack

I have a problem with the Yamaha 115 can't find any help you can run it like 28 mph all day long but if you open it up and start trimming it out in a second or two wants to shut it down for a second restart it and it runs long as you don't go over 28 mph but if you open it on up it does the same thing there has been few times when I first put it in the water I can open it up and run it wide open for a little while and it starts doing that

What it the course my 85hps Yamaha is consuming too much of fuel

This was a complete waste of time, I can't believe any marine maintenance company would produce some bullchit like this!

my motor goes good for 20 minutes then the primer is flat, after keep squeezing the primer for 5 minutes then the motor starts but only runs max 5 knots all the way back to the boat ramp if i try go faster it stalls, any ideas because it does go fast for the first 20 minutes every time I go out then primer flat again? I dont think its a blockage as it runs perfect for first 20 min each time. Please help...

I have a 1995 120 hp outboard after rev up and put it in nurture my rpm it wont go down why?

Not a bit of actual info..

Name is Wade swapped lower end on out drive but now won’t accelerate smoothly motor Boggs down like wants to die motor responds nicely in neutral

Nothing was any helpful to me

Honda 225 ,2003 , its always the vst tank , from fuel being stale , sure wish we could buy real fuel these days , twice it was the vst tank , its doing it again , i havent went through it , (this time yet ) but im already to blame the fuel again , and poly tank manufacturer's are idiots , they sag on top and hold water ,no way to repair that without ripping it out , with the whole floor , always where the fuel gauge hole is ...its not rocket science its a plastic gas tank ...aluminum is not the greatest either , but its about all there is ..

Boy did that video suck

Not helpful at all… “if your boat is running slow, it’s probably because you need to wash it”… Check you fuel system, carburetors, injectors, fuel pump etc.

trumps fault

Waste of time

speak english mate