08
Feb
When it starts to lose power I can squeeze the bulb once to keep it running for another 30 seconds or so until it starts running weak again. It seems to be a fuel issue.
Could leak out a full bulb of gas and maybe more.
Outboard motor loses power at full throttle. 15HP evinrude losing power at full throttle. Could be at least 3 things. I had fun with the same outboard last summer.
The fuel pump might need attention dirty screen bad gaskets the carb might need rebuilding or as I found besides a carb problem. Another possible reason your outboard motor is struggling to reach full speed is an air leak in your boats fuel line. In case this happens there will be a constant fluctuation in the fuel supply pumped into your boats carburetors.
As a result you will experience your outboard motors RPM fluctuating up and down. After a couple months went by it started acting up again when I am at full throttle it revs all the way out for a few min and then starts to lose rpm every 5-10 seconds like its starving for fuel. I have noticed though when I pump the primer ball when it starts loosing rpms it runs strong.
30hp model AE loses power at 34 to full throttle. It seems to be a fuel issue. When it starts to lose power I can squeeze the bulb once to keep it running for another 30 seconds or so until it starts running weak again.
Squeeze bulb and it improves. One possible reason why boats no longer achieve appropriate speeds at full throttle is a spun prop. This occurs when the bond between the propshaft and blades are broken which subsequently causes the rubber insert to spin independently.
When I try to run the boat full throttle it will bog right down after a few mintues of running. I tach out at around 4200 rpm and about 12mph. If I keep the throttle backed off a little from full it will run fine but I would like to get as much speed as I can out of her.
My owners manual says I can run this motor full at 5400 rpm max. Its a 90 hp mariner 2003 outboard 3 cylinder 2 stroke. All the cylinders have pretty similar compressions tried 2 different tanks of fuel so dont think it is the actual fuel or the fuel lines but will get some additive and try that.
My next step is to grab an inline spark tester and check for spark to try and Eliminate as many issues as I can. If I gave her a little more and got up near 5000 rpms the motor would bog down and start to sputter. When this happened I backed off the throttle and got it back up to 4500 rpms where it ran smooth again.
The motor would not die it would just bog down and lose the power. 45 horse mercury outboard runs fine till warm then loses power at full throttle. Throttle is reduced and it starts to rev up then bogs down.
Like the title says 1999 50 HP Merc 2-stroke losing power at wide open throttle. Things that have been suggested from bar stool Merc techs. Fuel filter fuel pump fuel lineprimer ball.
Primer ball in the fuel line seems to be holding firm. First time I pumped the ball this weekend it didnt release and stayed compressed. If your outboard engine is sputtering at any speed idle or full throttle it could be the result of several common malfunctions.
You may need to make a few timing adjustments or replace a spark plug or you may need serious mechanical inquiry. I am new to outboard motors I know what the VST is and where it is but dont know what it does exactly and why air leaks would cause less fuel. Would an air leak cause fuel to leak.
There are no signs of fuel leaking. Bobs201 New Member. My 2003 2 stroke 150 merc runs fine at 12 throttle but dies out at full throttle after about 3 mins.
It begins to sputter until I either ease off the throttle or it shits off. It it hard to start after shutting off and cranks similar to trying to crank it with the kill switch off. I have changed the fuel filters had carbs.
Idled fine prior and continued to idle fine wouldnt die at idle RPMs. Approximately half throttle it bogs a bit and seems to not be getting full power. Boatmotor doesnt want to pop on the hole shot and plan out like usual.
Seems to be starving for fuel as. A 1979 Johnson 85-HP Seahorse starts great and idles great and its take off seems alright until about quarter-throttle. Then there is no power after that.
A 1979 Johnson 85-HP Seahorse just runs at a very narrow band of engine speed of 1500-RPM to 1550-RPM fast enough to create a tiny wake behind us. That could sure explain the reason for power loss at full throttle as it would be pulling in a lot of air. This may also be draining out fuel when motor is not running.
Could leak out a full bulb of gas and maybe more. If this connection is not good would for sure check all connections to be safe. Everything from fouled or corroded spark plug wires to debris in the gas can cause sputtering or loss of power.
The first step is to identify what the cause of the problem is. The easiest way to do this is by eliminating the simplest explanation first and working your way outward until you locate the issue. The most obvious answer is fuel.
I also put a can of heet in it before I started out. Started up at first crack. Got up to full spped and them lost power.
Didnt run poorly just lost half power. Used my kicker then and it ran fine so gas cant be too bad. Still think it is a fuel problem.
Will drain 12 gas put in a can of sea foam and change the fuel filter. All engine-mounted filters including VST have been changed as has the hull-mounted 10-micron filter and I still have the original problem. Engine ran fine for 15-20 minutes through no-wake zones and the first few minutes at power 4000 rpm.
Then power dropped out like throttle had been retarded to idle - it went down to 1000-1500 rpm and then would surge back to 3000 rpm then. Yamaha 40hp 2 stroke I have a manual tiller 40hp EX40 2 stroke outboard motor engine having issue with engine cannot rev up. The engine starts up perfect but when reving.
225 horsepower Yamaha ox66 My 225 horsepower Yamaha ox66 starts up just fine but smokes more than usual at. I have a 2008 4 stroke Mercury 60 bigfoot on pontoon boat. When I attempt to go full throttle it will run fine for a few seconds and then start bogging down andor lose power.
It started doing this late last summer and I looked at it for a couple weekends. I have a Johnson 70HP 3 cyclinder outboard that usually runs fine. Sometimes it loses power to about 5mph at full throttle.
That may last seconds or 1 hour then fine for a week or loner. This has gone on for years. I can put multiple tanks of fuel through in a weeks vacation and it may run fine.
Ive taken it to a mechanic with no results. 45 horse mercury outboard runs fine till warm then loses power at full throttle. Throttle is reduced and it starts to - Answered by a verified Marine Mechanic.
I have a 1979 Evinrude 50hp outboard motor that starts easy and idles perfectly. When I first put the boat in the water it will run perfectly until it gets warmed up.