No Power In Forward Gear

[Mariahshabah]

Hello, I am the proud new owner of 1997 Mariah Shabah 190se. The boat has a 4.3l x gen with an alpha one outdrive. The boat starts, runs, and idles fine. With throttle only the boat will rev wonderfully. Once put in gear however the boat will not get over 5-10 mph and will not plane. Originally we swapped props hoping the hub was the issue only to end up with the same problem. The boat will reverse fine also. So basically I have no power under load. If anyway could point me in the right direction I’d really appreciate it.

I recently removed cap and rotor and the point were kind of gunked and also the boat was not winterized this last season. As of right now the tach doesn’t work but in “throttle only” I can rev the engine up no problem. It’s once I’m in the water the nose of the boat will raise up but doesn’t have the power to get on plane or speed up.

 

[Bt Doctur]

Is this with the drive fully tucked inward? Did you do a water test before purchase? Did it ever run good?

 

[Mariahshabah]

It ran great before it sat. It was given to me by a friend after a winter of neglect and I’m trying to get her back on the water. The drive is all the way down and regardless of trim boat will not speed up. I will try a water test.

 

[Bondo]

Ayuh,...... Welcome Aboard,..... Sounds like bad gas, or crap in the gas,.....

Examine the Contents of the fuel filter for anything but clean fresh gasoline,.....

 

[wellcraft-classic210]

Hi

----Any corrosion on the dip stick ? Milky oil ??

I ask as i had a 4.3 in a truck that had a leaking intake gasket that caused corrosion of the distributor cap quickly but was not bad enough to make milky oil-- It did rust the dip stick

Marine engines are prone to water intrusion from cracked blocks & damaged exhaust manifolds in not drained in the winter & then allowed to freeze. Not sure what " Not Winterized refers to in your post "

----- Regarding loss of power -- A few ideas for things to check

Does the engine sound smooth or bog ? Low fuel delivery will often cause you symptom of low power but the engine will tend to bog ( loose rpm's ) .The fuel filter is often a primary suspect. ( as bondo mentioned -- check the contents for water etc)

Have you verified your throttle opens all the way & the choke comes off ?

Fuel quality could be a problem -- Rig up a temporary fuel source if that's suspect


Compression & fuel pressure checks may be helpful if nothing simple is found

 

[Mariahshabah]

I have verified that the throttle is opening completely. What are some easy ways to check for fuel in the water? The boat has been sitting still on the trailer for a week so I don’t want just a gas sample off the top. Also the last time it ran the owner thought it had ran out of gas then put it back on the trailer then left it out in open storage over this last winter. When I got the boat a freeze plug was laying in engine compartment so I pounded it back in. So far it’s been through multiple heat cycles and no leaks thus far. Only issue now is lack of power. So my plan of attack as of right now is to check the quality of my fuel (in tank) and that the choke is coming off. (Unsure of how to verify). Thanks for all your help again.

 

[Rick Stephens]

A '97 should have a spin on canister water separator filter. Take it off, turn it upside down into a baggie. See what kind of crap comes out.

I would be pumping out ever last drop I could get to - problem with a tank left mostly empty is it then proceeds to condense water out of the atmosphere. Also check the filter screen into the carb - and if mine, a carb kit to get it clean and perfect as well..

A motor that dropped a core plug is likely to have cracked. Those plugs are not to protect against freezing and not really called freeze plugs. They fill holes left in the block to get the sand out during casting. Just so happens they also pop out when you freeze the water inside. They don't do a good job protecting from freeze damage, just telling you that you might have freeze damage, is about all they do other than fill a hole. SO don't be surprised f there are cracks.

 

[Mariahshabah]

Thanks for the info! I’m going to drain the tank and clean carb the best I can.

 

[Bondo]

so I don’t want just a gas sample off the top.

Ayuh,..... You'll find Good gas at the top,.....

Crap, 'n water is heavier than gas, so it'll be on the bottom, where the fuel dip-tube sucks it up,.....

 

[Mariahshabah]

Not seeing much if any separation from filter.

 

[harringtondav]

I'm with Rick Stephens . Once you've verified a clean fuel supply, I'd throw a kit into the carb, or at least disassemble it, soak it, and use an aerosol cleaner with a spray straw to flush out all passages. Especially those small transition passages that the valve plate sequentially uncovers in your bores. Then finish with compressed air.

It doesn't take much fuel to cause an engine to rev., but the carb must be able to deliver a lot of gas to generate power under load.

 

[kawakx125]

did you put on a brand new prop? certain the one you put on doesn't have a spun hub also?