Mercury/Crestliner wont plane

[gk1963]

Just bought a 2004 Crestliner Fishhawk 1650 with a 60HP 4 stroke EFI. The motor starts easy, runs smooth, and can troll all day without without any hesitation. The problem I have is the boat will not get on plane. It does not matter how i trim it. The motor does not rev up either. After maybe a minute on glass water in manages to climb op to plane then screams up to 30 MPH. I talked to a local shop and they told me the boat is underpowered since it is rated for up to a 90HP.
I have a hard time believing this though. My old boat was a 19 foot alumacraft competitior which weighed almost 1200 lbs not counting the 3 batteries and gear and it had no problem hopping onto plane with a 60HP mariner. Also my buddy has a 17' lund angler ss with a 60 HP merc. His boat is roughly the same size as mine but 300 lbs heavier.
The previous owner said he had the prop rebuilt. Could this be the smoking gun or could there be an internal engine problem?
Any suggestion would be helpfull.

 

[carholme]

Re: Mercury/Crestliner wont plane

You say that it does not rev up, yet go on to say that it screams at 30mph. Do you have a tachometer and if so what is the rpm you are getting at full throttle?

What is the engine s/n?

Gerry

 

[gk1963]

Re: Mercury/Crestliner wont plane

Sorry Gerry. First time thread user here. I might have sent you a message on accident or something. To clarify the motor will only run at around 1500 rpm at best while trying to climb onto plane. If I am alone with 1/2 tank of gas and 1 starting battery it will manage to climb onto plane after 1 minute or longer on glass calm water. Once it gets up on plane it will accelerate to 30MPH and be running about 2800-3000RPM according to my tach. It gets stuck at 9MPH and around 1500 rpm while tryong to climb up to plane. If i have another body with me in the boat it will not plane out no matter how long I give it. I will get back to you with a S#

 

[Silvertip]

Re: Mercury/Crestliner wont plane

Keep running it and you will destroy the motor as it is being lugged severely. That engine should spin to 6000 rpm so here's the sequence of checks. Some you can do some you can't.

1) Check to see what prop (diameter and pitch) is on the motor. Those numbers are something like 12x15P or similar and are located between the blades or on the hub behind the prop nut.
2) A motor that is not making full power obviously cannot perform as expected. Have you pulled the plugs for a look-see. That alone can tell a story. Black and oil soaked = an oil burner, fuel issue, fouled and not sparking. Replace them if necessary. They should be nice light tan on a fours-stroke.
3) Check for spark on all cylinders. Use a timing light or a cheap spark tester available at any auto store.
4) It wouldn't hurt to do a compression check to make sure the engine doesn't have a bad cylinder or two.
5) Verify that the tach is accurate. I doubt this since 30 MPH at 3000 rpm is not likely with that engine since 6000 rpm would yield 60 MPH or thereabouts and that really is not possible.
6) A bad fuel pump, bad injectors (fuel injected engine) or bad carbs on a carbureted engine can cause starvation and lean running which results in poor performance.
7) If all of this fails to turn up anything, a trip to the shop is necessary.

 

[jeffersondodson561]

Re: Mercury/Crestliner wont plane

4) It wouldn't hurt to do a compression check to make sure the engine doesn't have a bad cylinder or two.
5) Verify that the tach is accurate. I doubt this since 30 MPH at 3000 rpm is not likely with that engine since 6000 rpm would yield 60 MPH or thereabouts and that really is not possible.
7) If all of this fails to turn up anything, a trip to the shop is necessary.

Definitely
if everything checks out verify fuel pressure at fuel rail...post serial number (for all viewers posting serial/model number is crucial for all brands) if this fuel pressure regulators vents to atmosphere...regulator may be culprit.