Manifold and Risers Replacement

[BMsuper]

New to boating! 1988 Mercruiser 2.5 with Alpha 1 outdrive.

I am presently replacing a manifold with a hole in it. Are the Manifold and Riser a normal maintenance/replacement item every 4 or 5 years? I've also replaced all the bellows and rubber transom items. What else should I be looking for.

Thanks, Bob

 

[mthieme]

Re: Manifold and Risers Replacement

I have read somewhere that you should take them off every 4-5 years for cleaning and inspection. Noone I know does this.
There are so many things that can wear it would be hard to list.
Anything steel comes to mind.
In the past two years I've replaced my PS pump (reservoir rusted out on the bottom), the heat exchanger for the PS fluid (pinhole), starter (solenoid damage from repeated submersion), several terminal connections, and I'm sure I'm forgetting something....

 

[chiefalen]

Re: Manifold and Risers Replacement

Riser if used in salt water 5 years. Manifold mine still good 22 years latter.

Flush the system every time you come off the water.

I would if it were my boat, clean every electrical connection.

Everyone including the grounds. Most forget there are 2 ends to every connection.

Make sure the cables are good and clean.

Clean the connections on the ignition switch.

All the other connections under the dash they green.

T-stat good? Put a new one in now or just before you go out next year.

How's compression?

When was the last tune up done?

Full tune up?

Belt looks good? Tight?

Hoses look good?

Getting a good charge around 14+ volts out of the alternator?

Got a working bilge blower, maybe the most important or second to the bilge pump piece of equipment on the boat.

Got a anchor? All the other stuff the cg requires?

Out drive how the oil look? It shift good.

Welcome aboard i'm sure theres more i have crs.

 

[BMsuper]

Re: Manifold and Risers Replacement

So far I have rebuilt the carb. changed the points and condensor, new spark plugs, the belt looks good, new drive shaft bellow, throttle bellow, exhaust tube, check the gimble bearing, installed a two battery setup with switch not to mention all the cosmetic work.

The oil in the outdrive and engine look good but end of season both are getting changed. Just received a new impellor kit to go in and the new manifold and risers are in shipment. All the hoses look good, it's charging good but one thing I have to fix is the engine cut out switch when shifting.

I read in the forum that the switch is supposed to kill the engine for a second while shifting into gear. The former owner must have dismantled it from the throttle up front as it does not move when shifting into gear. I have the idle so low I never noticed that it didn't work. As soon as the manifold is done thats the next project.

I really like this boat and the grandkids love to fish so I will probably always have a boat now. I took an ABC Boating course (8 hours) and learned a lot. Its got GPS, depth finder, 2 fish finders, a marine radio and all the required CG stuff.

I haven't done a compression test yet. It ran so good, even with the small hole in the manifold I can't wait to get the new one on.

By the way, I couldn't handle this boat without this forum. I am very good mechanically but I just don't know much about boats. I have all the manuals and with this forum's help I'm able to maintain it myself.

Thanks guys. Bob

 

[achris]

Re: Manifold and Risers Replacement

...I read in the forum that the switch is supposed to kill the engine for a second while shifting into gear. The former owner must have dismantled it from the throttle up front as it does not move when shifting into gear. I have the idle so low I never noticed that it didn't work. As soon as the manifold is done thats the next project....

Sorry, wrong.... The switch momentarily stops the ignition ONLY when shifting OUT OF gear. If the PO disconnected the switch it was probably because it was killing the engine when going INTO gear, usually caused by a sticky shift cable, usually caused by the intermediate shift shaft seal leaking water in to the shift slider cavity.... You have some work to do.

Chris............