Mercury Verado 250 is an outstanding engine. It comes with superior power, splendid outboard design and the best fuel economy.
The instant L6 torque on throttle powers your heavy offshore boat. The engine is much quieter due to its acoustic engineering. Even at wide-open throttle and high speed, it delivers excellent fuel economy.
They claim corrosion resistance in saltwater usage too. Additionally, a 3-year resistance warranty boosts that claim.
However, there are many common complaints against Mercury Verado 250. The engine’s recent years did not support it very well. I will discuss those in this article with some customer opinions at the end. So read on!
1. Oil Leak:
The oil squirters exist to lubricate the cylinders. This design of the block suppressed horsepower. And connecting to PCMs would not give you more horsepower. Motor oil is found spilled on the outdrive.
Oil is found on exhaust ports as well. Oil especially leaks when the boat is tilted. Also found from the base of the trim.
The oil spillage sometimes causes a lack of compression on cylinders. Particularly on cylinders 5 and 6. This issue of the engine is totally mechanical.
2. Sticking of Shift Crank:
Seizing of the bell crank would occur in the engines that were first released. This would cause losing control of shifting the engine. You can hear buzzing noises from the cowling when this happens. Sometimes you can get stuck in forward or reverse gear.
3. Back Pressure Blow Out:
A hose connecting the supercharger with the Electronic Boost Controller causes problems. Add another one in this group which is connected to the intake manifold via the boost controller.
These can blow a hole in the tube. Especially during a specific load, pressures, backfiring, throttle chopping, etc.
This causes revving of the engine as it intakes a lot of air. This may cause a wide-open throttle.
4. Powerhead Oil Pump Leaking:
Some seals around the driveshaft tend to leak. The leaking oil will then run down along the driveshaft. Thus the engine loses oil.
Due to lack of servicing, there occurs buildup on and around the seals. Especially due to saltwater excursions.
Sometimes, the driveshaft gets locked to the powerhead due to bad seals.
Replacement and maintenance are a bit difficult due to the complicated mounting design of these parts.
5. Ignition Coil Failure:
The ignition coil frequently fails in this engine. There used to be a problem with the cover of the engines.
The coils mainly fail due to an overheating issue. They would even fail similarly when they are cold. So there is no saying why they fail.
Although the coils have been redesigned and launched in 2008-2009. But second-hand purchasers can just as easily be buying an engine with this issue.
6. Tearing of Isolator & MAP Boot:
The boot connecting the Electronic Throttle Control unit to the bottom of the supercharger is called the Isolator boot. Air leakage in the supercharger would occur as this boot would tear at the bottom.
As a result of the leakage, the engine would be pushed to higher RPMs. One of the manifestations of the problem is higher idles. Another would be loud airy noises from the engine.
The hose clamp connecting the boot now demonstrates problems. These can rust, ultimately breaking. Consequently, detaching the entire throttle body from the supercharger.
Moreover, problems with Manifold Absolute Pressure Sensor was also found sometimes.
7. Failing Lower Unit:
The Verado initially had a 4.83-inch diameter gearcase. Due to overhauling after the initial launch, the gear case could not hold up well. So the lower unit started failing repeatedly.
This size was pushed up to a 5.44-inch. However, a smaller gearcase drags less in the water.
8. Lift Pump/Float Switch Problem:
The engine’s Fuel Supply Module (FSM) has a float switch. This switch controls the level of fuel controls the amount of fuel to go into the container.
Turning up the switch shuts off the fuel lift pump. The switch is prone to get stuck at the top. That is it gets stuck in the ‘turned up’ position.
As a result, the lift pump is kept shut. So the engine runs out of fuel.
9. Trim Problem:
When the trim sensor fails, the RPMs of the engine get decreased unintentionally. That means, delivering less performance in terms of speed.
The trim sensor tells the trim range of the engine. For this, a pin has to spin a knob on the sensor while trimming up.
The sensors failing is a pretty common issue of the engines. Changing sensors frequently is an issue.
10. Time Jumping:
A timing chain is an integral part of the Verado engines. It helps in running the engine.
The engine was found to jump timing. It is not an issue if it jumps a single tooth. That can be taken care of.
But jumping time can cause the valves to get shattered completely.
Although looking at such a wide range of problems is terrifying. The good news is that Mercury’s new Verado engines have a lot fewer problems.
Even when they do, they have a less severe version of the problems mentioned above.
The benefits in terms of speed and quietness are very exciting. Especially for cruisers and fishermen.
I recommend purchasing the engine for a satisfying boating experience.