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Surging and bogging in overboard motor(obm)

Water boat engine

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2011 seadoo boat 150 speedster surging up and down on full throutle but idles fine in neutral and changed the plugs and new gas and tps sensor and still no differnce


Check for air leaks on the manifold, or fuel air locks, fuel starvation. Tank vent, kinked pipes, that sort of thing.

There is further help in the link.

This is caused by minor cavitation. It is not an actual issue. What is happening is that your impeller is moving fast enough that it's drawing out the available supply of water since the boat is moving slowly and there isn't enough pressure on the bottom of the boat the keep the jet pump fed with the amount of water you're expelling out the nozzle. Water is fed into the tunnel in the transom by the pressure caused by forward motion at speed.

Every jet boat will probably do it at a certain RPM depending on many different factors even down to water temperature, fresh/salt water etc.

For the longevity of your wear ring and impeller...avoid that rpm.

2011 seadoo boat 150 speedster surging up and down on full throutle Google...

Aug 14, 2017 | Cars & Trucks

1 Answer

What will make a johnsonew 50 hp out board motor bog when under load


Evinrude 50 HP Bogs at WOT - MarineEngine

www.marineengine.com > ... > Johnson Evinrude Outboard Archive

Aug 6, 2002 - 17 posts - ‎3 authors
83 50 HP Evinrude - sat out in weather for 4 yrs. Been cleaning ... At WOT, she bogsdown. Up to. ... Yes, this boat/motor is new to me. Actually ... Mercury 50 1987 bogs down when full @ full throttle
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Motor Runs great bogs down under load.
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Dec 09, 2015 | Cars & Trucks

1 Answer

My 88hp Johnson won't tilt up when moving in water unless I am going slow therefore I can't get topend speed what would cause this?


outboard motors some times are designed to not run at speed while tilted as the water pump inlet is above the water line and the engine will over heat and the pump impellor will be destroyed.. With an engine tilted the load from the propeller tends to lift the nose of the boat high and makes it unstable on the water . The best situation is to have the propeller tend to drive the nose down thereby promoting a planeing action that improves economy and speed Once the boat is on the plane you can cut back on the throttle and still maintain the same speed . Moving with the leg tilted should only be used to navigate shallow water at very slow speeds

Jan 26, 2014 | Cars & Trucks

1 Answer

97 toyota surges at an idle


(which engine. ?????)_
as always check all fuses. and scan the ECU for DTCs. first.
there is no need to fix OBD2 cars like 1980 cars (hard rows to hoe)
it can be 2 problems this......
lets fix the easy one first. idle. (and hope for moving issues to fix for free) it idle car is parked, so is 100% safe tests. (not moving)

so it surges at idle.
questions.?
1: hot or cold or both.?
2: low extreme RPM and high at idle.

400 to 800 RPM? surge.
1000 to 2000. what? numbers tell the tale.

first off, idle is the last thing to work right on any engine.

there are many ways to find what is wrong.
fix idle surge way.
i make sure that the engine holds closed LOOP status.
hot idle, if not , i fix that first.
keep in mind if not in closes loop and lean
all lean engine surge and guess what the ISC will add to the surge
because idle is way too slow, so the ECU open the ISC wider
and wider and its still too slow, so the ECU resets the ISC
this cause a worst hunt (surge)
the ECU adjust spark time and the ISC to get 800 rpm. (spec. look up yours)
so say , i see closed loop failed, OBD2 scan page 1
i look at the O2 sensor an its stuck lean.
if stuck lean and it really is (o2 bad?) then its lean and it will surge
.
examples.
1: i find 02 sensor bad, (only effects idle and light steady cruise)
2: i find fuel pressure at 15PSI , hopeless low .
3: i find all injectors clogged. and lean.
4: with MAF EFI, ( i find maf reading too low, (dirty) causing lean.
5: if MAP car, i find the MAP stuck hard high vacuum causing lean.
not knowing what engine you have or the idle hot surge range,
i can not go farther.

the driving bog tells me,
1: scan the ecu ,get DTCs; do that first.
2: clean MAF if car has one, ask how..
3: check fuel pressure.


my guess is engine is lean. and starving for fuel all the time.
cept WOT.

MAF cars starve for fuel if there are any vacuum leaks.
MAP cars do opposite, they race fast with 100% full power.
MAF is air density EFI
MAP is speed density EFI.
apples and oranges diffr. so what engine.


Jan 07, 2014 | 1997 Toyota Tacoma

1 Answer

1989 2.3L ford cobra boat inboard motor water getting in motor oil


Not much on boats, but it sounds like it is definitely a cracked head, or a blown head gasket. You could have catostrophic failure if you run engine in this condition.

Aug 09, 2013 | Cars & Trucks

1 Answer

HAVE A 1999 CADILAC CONCORS CAR WONT TES FOR OBM.INSTALLED A NEW BATTERY AND CAR MUST RESET. i DONT KNOW HOW ?


you need to drive it about a week of normal driving or two days of driving as close to 50mph for 10 miles straight

Sep 28, 2012 | Cars & Trucks

1 Answer

Having trouble with my 1974-78 outboard marine engine


Just an idea but your water pump is only rubber and setting for the winter it didnt stick to the sides of where it pumps did it.. sometimes these pumps are tempermental.. you might check your water pump again making sure its pumping right.. is it peeing out the sides good like it is suppose to ? also if its getting hot on top it makes me think the pump is not doing its job right maybe just pumping some.. not enough? just a thought .. thanks Jerry

Apr 27, 2009 | 2004 Mercury Mariner

1 Answer

Boat not responsive


hi, thats a little motor for a big boat. how big is the boat? you can try changing the timing by loosening the distributor cap and turning it slightly to see if that helps or you can get a different prop that has less pitch on the blades which will spin the prop faster in the water and keep you up in powerband better. maybe call a marine boat shop and tell them your problem, maybe they have a trick or two. happy boating J

Aug 15, 2008 | 1989 Ford Taurus

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