1987 wellcraft slow out the hole 170 hp

[bamaeddie]

I have a 1987 Wellcraft 19 ft. 170 hp Mercruiser inboard. Slow getting out of the hole but feels like it runs good in top end but only getting 2200 - 2800 rpm's. Boat is rated 4200 - 4600 rpm. Not sure if tac is wrong, I have a 19 inch pitch prop on it. Could someone please tell me what they think might be wrong??

 

[Bondo]

Re: 1987 wellcraft slow out the hole 170 hp

Ayuh,... Welcome Aboard,...

How long has it been since the motor had a Full Complete Tune-up,+ Compression Test,..??..??
Has it always run like this, or is it something New,..??

The Tach should be verified, or replaced...

 

[Don S]

Re: 1987 wellcraft slow out the hole 170 hp

Once you know your tach is right, here is a list of possible causes of low WOT rpm.

Engine Won't Reach Operating RPM. Check

• Fuel condition. Type and Octane possibly old fuel
• Propeller pitch or diameter, damaged blades
• Restricted fuel pickup tube or anti siphon valve Fuel System Test
• Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
• Marine growth on hull and outdrive
• Wrong gear ratio in outdrive
• Restricted carburetor air intake (clogged flame arrestor)
• Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
• Poor cylinder compression Compression Test
• Carburetor defective, or wrong type.
• Fuel pump pressure and vacuum
• Boat overloaded, improperly loaded, or improperly trimmed.
• Engine Overheating
• Engine timing and ignition system operation
• Remote control cables and linkage for proper travel to open throttle plates fully.

 

[kikroks]

Re: 1987 wellcraft slow out the hole 170 hp

what is your mph if your going fast enough your rpms may be wrong you can usally tell by the sound of the motor 2800 rpms you should roughly be going 25 to 30 mph max . if your mph is 35 to 45 your rpm are reading wrong , and for slow out of the hole ,i recently went from a 3 blade 22degree to a 4 blade 18 1/2 degree now i am way qiuicker out of the hole with minamal bow lift but lost a couple mph top speed so i hope this helps