Power loss at full throttle

F

flyingcr

.
Nov 30, 2016
10
Beneteau 1993 265 first Houston
I have a First 265 with a volvo penta 10hp.
Cruising around at 3.6 knots just wasnt getting me back quick enough. When I went full throttle, the engine lost power and wanted to stall. Bringing throttle back some saved stall and engine worked fine, but doesnt like full throttle. Any reason for this?
Chistiona
 
kloudie1

kloudie1

.
Nov 6, 2006
10,095
Hunter 34 Mandeville Louisiana
sounds like a fuel feed problem.. plugged filter would be first, then an air leak at a connection prior to the pump (might even be the packing of the fuel shut-off valve).. a plugged inlet tube .. (the tip of the tank pick-up tube sometimes has a little screen that can plug)... bad lift pump..
 
NYSail

NYSail

.
Jan 6, 2006
3,145
Beneteau 423 Mt. Sinai, NY
Also could be an exhaust related issue..... Any smoke coming out exhaust pipe and if so what color??
 
B

Benny17441

.
May 24, 2004
7,174
CC 30 South Florida
For future reference Black Smoke is incompletely burned fuel, Bluish Smoke is burnt oil and White Smoke is water vapor but sometimes the shades blend into each other and at times oil, water vapor and unburned fuel might look the same. What is it, 80% of diesel engine problems are fuel related. Yours sound like fuel starvation at higher RPM so I concur with Kloudie that you may have a plugged filter. I would just replace the fuel filters but take a special look at the water separator and insure there is not an undue amount of water in the fuel and that you may be using the proper microm size element. There are other causes like Kloudie and NYSail have mentioned but start at the maintenance issues before moving to possibly failing components.
 
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jibes138

jibes138

.
Jan 27, 2008
3,086
ODay 35 Beaufort, NC
Take a ziploc bag or mason jar and pump some fuel out of your tank before any filters. Should be perfectly clear, if it is cloudy or slimy looking, maybe with some sediment you should empty and clean the tank. Changing filters might buy you some time but a contaminated tank will continue to frustrate you.
 
Sailvernon

Sailvernon

.
Oct 27, 2010
3
Beneteau 323 Vernon
I had a similar problem, the engine would run fine at 2,200 rpm but anything over 2,500 rpm would cause the engine rpm's to drop off and sometimes even stall. And then it would be fine at 2000 rpm again!
After checking the fuel, changing fuel filters and checking for fuel line leaks or restrictions ....it ended up being the lift pump. I installed a new lift pump and the problem went away. According to the supplier this is a common problem with lift pumps.
 
nfg2u

nfg2u

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Feb 13, 2016
92
Hunter Legend 35.5 Fort Pierce
Get an inline suction gauge and put between the fuel filter and the motor fuel filter. If it reads other than 0, then you have a restriction some where. Start with the filter.
 
Ted

Ted

.
Jan 26, 2005
1,272
C&C 110 Bay Shore, Long Island, NY
nfg2u said:
Get an inline suction gauge and put between the fuel filter and the motor fuel filter. If it reads other than 0, then you have a restriction some where. Start with the filter.
Click to expand
I have to disagree with nfg2u's statement. The only time a vacuum gauge will read zero is when the engine is off. With your engine running, the vacuum gauge will indicate a very low reading when you first install a new fuel filter but the reading will gradually increase over time until the filter is so dirty that it restricts fuel flow causing your engine to slow down or stop.
 
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jssailem

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,179
CAL 35 Cruiser #21 moored EVERETT WA
SBO sailors strike again. And another boater is saved.... This is such a great group.
 
nfg2u

nfg2u

.
Feb 13, 2016
92
Hunter Legend 35.5 Fort Pierce
@Ted, Thanks for the feedback. You are correct, as the filter does its job and collects particles from the fuel and or water then the suction will go up. Also depends on where the tank is installed. Where is the gauge installed in relation to the tank? Is it bellow or above? Also if the tank is almost empty then there may be some suction to get the fuel from the tank. If there are no restrictions and there is a new fuel filter, the gauge should read near 0 if not 0. Mine runs at 0 with a new filter installed.
 
jssailem

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,179
CAL 35 Cruiser #21 moored EVERETT WA
For those who enjoy pictures.
Here is what a dirty filter looks like when the engine shuts down from fuel starvation.
IMG_1169.JPG
The vacuum gauge would be showing up somewhere in the plus ten range. The engine just starves for fuel. It races a bit maybe a surge then quits.
When it gets this bad you have to change the filter and prime the fuel lines as you will have sucked them dry.
 
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Mechone

Mechone

.
Mar 20, 2016
595
Beneteau 351 WYC Whitby
gauge-main.jpg
I had problems , installed a vacuum gauge after filter between engine 0-6 inches of water I coloured green 6-10 yellow and 10 -30 red . It read 0 for about a week and over the season has gone up to 4 my filter is very high micron racor r24s 2 micron .My gauge is also glycerin filled for vibration. the pic is not mine but you get the idea.Change out filter when it hits the yellow
 
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