Mercury 4 Stroke Acceleration concern

[MarineJunkie2.0]

Hey all! I'm a 1st time pontoon owner as of 3 weeks ago. Bought new with Mercury 4 Stroke and it ran beautiful the 1st day with the salesman and I (ran @ 20MPH w/ no problem). On day 3 however, I noticed the boat will not accelerate past 12-15MPH while RPM's running at 6-7. Motor sounds like it's trying to get up to speed - but no success. I am extremely frustrated b/c I've done nothing different. (I've tried trimming it UP - but still no results).

I'm reading things about some Mercury issues on here and I don't know if any of you might have advice or thoughts of what could be causing this? I appreciate any advice or feedback! Thanks, Chris

[MH Hawker]

sounds like the prop hub is slipping to me high rpm and slow speed

[MarineJunkie2.0]

sounds like the prop hub is slipping to me high rpm and slow speed

Thank you sir! I will look into that.

[Bamaman]

You can use a colored magic marker or grease pen to markem at the same place.

Then run it. If it's a slipping hub, the marks will not be together.

[MarineJunkie2.0]

You can use a colored magic marker or grease pen to markem at the same place.

Then run it. If it's a slipping hub, the marks will not be together.

Great idea! So glad I joined this sight. Thanks!

[slingshot]

Need more info:

type of boat and length?
motor size?
6 or 7 hundred or thousand RPM?
prop pitch and diameter?

It's a brand new boat so a spun hub would be unlikely unless you hit something. More likely the boat motor is set up wrong. If you're on the same tank of fuel your boat may be sitting higher in the water now as you burn off fuel. That can cause cavitation if the motor is set up to high. Tell your dealer, they should fix the problem.

[MarineJunkie2.0]

Need more info:

type of boat and length? LOWE's Pontoon 18'
motor size? Mercury 4 stroke 60HP
6 or 7 hundred or thousand RPM? 6
prop pitch and diameter? Unsure

It's a brand new boat so a spun hub would be unlikely unless you hit something. More likely the boat motor is set up wrong. If you're on the same tank of fuel your boat may be sitting higher in the water now as you burn off fuel. That can cause cavitation if the motor is set up to high. Tell your dealer, they should fix the problem.

It is brand new and very frustrating. I filled it up all the way with gas several days after purchase. (28gal). Good call because I did hear a POP like maybe a stick while cruising around but acceleration was an issue before. It doesn't make sense to me since it ran so great the first few days (20+mph), now struggling to hit 15 w/ throttle all the way forward. Appreciate your help!