150 HP Evinrude not reaching RPM´S

[regioangler]

Hi everyone!

I just bought a Champion 18´6 bass boat With a 1993 150 HP Evinrude Ocean Runner (20" gear case) seated on a 6" jack plate with a 14-1/4 x 23 Alumunium propeller.

The compression test result was 115-120 lb on each cylinder.

The hole shot is excellent ,but the top speed is just 45-47 MPH and just reach 4700 RPm´s

Where should I Start to make changes to reach 5400-5500 RPMS and increase my MPH??

I did Rise the motor with the jack plate 2" but I did not perceived substantial changes
.
Thanks in advance.

[mactlman]

post in evinrude section better-- sharp guys on there

[fastman151]

Sounds like a mechanical issue. Mt first guess would be an air leak in the fuel system! you could have someone squeeze the primer bulb while your running and se if the rpms pick up.

[Texas Rig]

Sounds very similar to what I just went through on my 1990 model 2-stroke Yamaha except for the good hole shot. At WOT, I could only get ~4500 rpms. Get a buddy and go to the lake,remove motor cover and carb intake cover so the carbs are exposed. Work throttle lever or hot foot to WOT position to see if butterflies are opening fully (horizontal), if not then you need a cable adjustment. If butterflies in the carbs are opening then launch and test run. While having the motor at WOT,have your buddy squirt gas into each carb one at a time. If no change in rpms during the squirt then carb is functioning good. If rpms jumps while squirting gas then that carb has a restriction and needs to be cleaned. I used a small bottle that eye drops came in, it doesn't take much gas. Good luck.

[ChampioNman]

Check these settings first, http://www.bbcboards.net/showthread.php?t=11790

Then check the prop to pad setting. http://www.bbcboards.net/showthread.php?t=62660

[ChampioNman]

I'd lose the aluminum prop also, you should be able to spin a stainless steel prop no problem.

[bill.s]

What RPM and speed did the previous owner get? That 23 pitch might be one pitch too high, I have a 19 ft Ranger with a 175 HP engine with a cupped 23 pitch and it works well.

[Bassman Ia.]

Isn't the top RPM's on that outboard 5250rpms? With 1.86 gears

[ChampioNman]

What RPM and speed did the previous owner get? That 23 pitch might be one pitch too high, I have a 19 ft Ranger with a 175 HP engine with a cupped 23 pitch and it works well.

No. But thanks for participating,

[regioangler]

Check these settings first, http://www.bbcboards.net/showthread.php?t=11790

Then check the prop to pad setting. http://www.bbcboards.net/showthread.php?t=62660

Thank you. I will check that settings

[regioangler]

Sounds very similar to what I just went through on my 1990 model 2-stroke Yamaha except for the good hole shot. At WOT, I could only get ~4500 rpms. Get a buddy and go to the lake,remove motor cover and carb intake cover so the carbs are exposed. Work throttle lever or hot foot to WOT position to see if butterflies are opening fully (horizontal), if not then you need a cable adjustment. If butterflies in the carbs are opening then launch and test run. While having the motor at WOT,have your buddy squirt gas into each carb one at a time. If no change in rpms during the squirt then carb is functioning good. If rpms jumps while squirting gas then that carb has a restriction and needs to be cleaned. I used a small bottle that eye drops came in, it doesn't take much gas. Good luck.

The butterflies in the carbs are opening without problem I wil do the gas test.

Than you.

[regioangler]

What RPM and speed did the previous owner get? That 23 pitch might be one pitch too high, I have a 19 ft Ranger with a 175 HP engine with a cupped 23 pitch and it works well.

I dont Know What speed he did get, the boat sat for a long time in a storage.

What is a cupped prop??

Thank you

[regioangler]

Isn't the top RPM's on that outboard 5250rpms? With 1.86 gears

I had a Johnson 150 hp that reach 5400 rpm, I really Dont Know what ratio gear does that motor had. Im supposing is the same gear in this evinrude

[regioangler]

The powerpack is new and I just bought the spark plug cables I will Install this next weekend.

[ChampioNman]

Isn't the top RPM's on that outboard 5250rpms? With 1.86 gears

Operating range is 4500-5500 with HP rated at 5000 RPM Rev limiter is 610.0 RPM