Manifold and Riser Maintenance

[belairboater]

Has anyone tried soaking their manifolds and risers in Muratic acid to clear them out? Mine are corroded inside and I believe that is why it overheats when idling for a period of time. As soon as I head out, it cools down but overheats again when idling.

I read an article on the internet, somewhere, that they actually suggest removing the manifolds once a year and soaking them in Muratic acid to clear out any build up from minerals in the water.

 

[SAshton]

REPLACE THEM!!!!! Don't waste your time my cleaning them. The corrosion eats away the cast(thinning the walls) and eventually will leak into your cylinders. If yours are all plugged up with corrosion then they have to be old and its time to replace them........

 

[fwebster]

Risers are not a cooling cavity so the corrosion is not such that an acid will remove it. All acid will do is to hasten the riser's demise by accelerating the corrosion.

As SAshton says, if yours have enough corrosion in them to affect cooling, then you are on borrowed time and you need to replace the castings. The price of delaying is usually a new engine.

 

[NorCal Boater]

Overheating at idle and then the temp going down while on plane or moving the boat faster, can also be a symptom of a week impellor in the outdrive. If it's weak it cannot move enough water into the engine to cool it when cruising at idle. Once the boat starts moving faster it forces water into the drive and up to the engine.

The other guys are right. Replace the manifolds and risers but do the water pump at the same time. Remember....there's never time to do it right but always time to do it over.

 

[osd9]

I agree...replace the mainfolds if you see corrosion.

Another possibility of running hot at low speed could be that the two "spring balls" (I'm not sure what they are really called) in the goose neck on the Thermo housing either have some debri stuck in them or that the springs/balls themselves are worn/corroded.

 

[belairboater]

Thanks for the help!!! I'm ordering them today.