troubleshooting hot manifolds

[produceguy]

Hi guys, I have replaced the water pump in my outdrive and on my motor and the thermostat. its a alpha1 gen1 v6 mercruser and the manifolds and the y pipe get so hot that i keep burning thru my lower shift cable. the motor never overheats, and a boat mecanic told me that the y pipe and the manifolds that the cable is resting on should never get hot. I am going to replace the cable and get some clips to keep the cable away from the pipe. does this sound like i have a bad manifold that is causeing the pipe and manifolds to get hot? Thank you guys so much for the help.

 

[Bondo]

Re: troubleshooting hot manifolds

Hi guys, I have replaced the water pump in my outdrive and on my motor and the thermostat. its a alpha1 gen1 v6 mercruser and the manifolds and the y pipe get so hot that i keep burning thru my lower shift cable. the motor never overheats, and a boat mecanic told me that the y pipe and the manifolds that the cable is resting on should never get hot. I am going to replace the cable and get some clips to keep the cable away from the pipe. does this sound like i have a bad manifold that is causeing the pipe and manifolds to get hot? Thank you guys so much for the help.

Ayuh,.... It sounds like there's a restriction at the water's exit from the risers.... or 'tween the manifold, 'n risers...

 

[wingless]

Re: troubleshooting hot manifolds

Disassemble the exhaust for inspection, then take appropriate action.

 

[produceguy]

Re: troubleshooting hot manifolds

Thanks guys, This might sound dumb but what might be blocking the path? I have replaced the flappers so I know or I think they should be good. I will pull the risers and manifolds but not sure what i'm looking for? Just crud?

 

[Bondo]

Re: troubleshooting hot manifolds

Thanks guys, This might sound dumb but what might be blocking the path? I have replaced the flappers so I know or I think they should be good. I will pull the risers and manifolds but not sure what i'm looking for? Just crud?

Ayuh,.... Rust, 'n Crud in the Water passages, not the exhaust passage...

 

[produceguy]

Re: troubleshooting hot manifolds

Thanks Bond-o.

 

[boatguya1]

Re: troubleshooting hot manifolds

Hi guys, I have replaced the water pump in my outdrive and on my motor and the thermostat. its a alpha1 gen1 v6 mercruser and the manifolds and the y pipe get so hot that i keep burning thru my lower shift cable. the motor never overheats, and a boat mecanic told me that the y pipe and the manifolds that the cable is resting on should never get hot. I am going to replace the cable and get some clips to keep the cable away from the pipe. does this sound like i have a bad manifold that is causeing the pipe and manifolds to get hot? Thank you guys so much for the help.

Canyon Lake? Hope I wasn't to short with you, I was pretty busy.

You might try firing it up for a few seconds with the hoses that go to the exhaust dissconnected to see what kind of flow you have there. If you have good waterflow then clogged waterjackets on the exhaust could be the problem. I think you told me the therm hsg was clear when you changed the therm so probably not there. What is your serial number?

 

[boatguya1]

Re: troubleshooting hot manifolds

http://www.**********/parts/search/Merc2/Mercruiser/4.3L%20-%20(2BBL%20GM%20262CID%20V6)/0B773243%20THRU%200D714106%20(1988-1992)/STANDARD%20COOLING%20SYSTEM%20NEW%20DESIGN/parts.html

If this is your cooling system it shows the rod/springs/and checkball assy I mentioned when I taiked to you. If it does not work properly the exhaust may get hot.

www.**********/parts/search/Merc2/M...STANDARD COOLING SYSTEM NEW DESIGN/parts.html
edit
for some reason the link did not work (to long?) you'll have to cut and paste

edit again crud, it keeps abreviating my link, I'll try again without the www.

**********/parts/search/Merc2/Mercruiser/4.3L%20-%20(2BBL%20GM%20262CID%20V6)/0B773243%20THRU%200D714106%20(1988-1992)/STANDARD%20COOLING%20SYSTEM%20NEW%20DESIGN/parts.html

Still no go I just googled 1988 mercruiser v-6 parts diagram to get to the diagram. I may know what's up looks like the software here may be ***** over a competitor's name in the web address I was linking for the parts diagram

 

[produceguy]

Re: troubleshooting hot manifolds

Canyon Lake? Hope I wasn't to short with you, I was pretty busy.

You might try firing it up for a few seconds with the hoses that go to the exhaust dissconnected to see what kind of flow you have there. If you have good waterflow then clogged waterjackets on the exhaust could be the problem. I think you told me the therm hsg was clear when you changed the therm so probably not there. What is your serial number?

Yes buddy that was me. No you wasn't short with me at all and yes you did look busy. Its going to be a few days before I get to dissasemble it but do you mind if I send you a pm if I have any Q on it.

 

[boatguya1]

Re: troubleshooting hot manifolds

I PM'd you my e-mail. Sometimes I don't get on this site for a while. Whatever you do that fixes the problem please post it here so others may learn.

 

[produceguy]

Re: troubleshooting hot manifolds

Hi guys, would I mess anything up if I pulled the thermostat out,reassmbled it and start the motor to see if the problem is the thermostat? I might of damaged it when I was installing it. I would def replace it,not run it like that. What do yall think is that ok to do?

 

[dingdongs]

Re: troubleshooting hot manifolds

when you changed the impellor was it complete?
you could see if the water circulating pumps impellor has come detached from the shaft,maybe slipping. .obviously driven via the belts.
flow seems to be the problem and are you sure the risers do not have any blockages.i.e. incorrectly installed gaskets and flapper rubbers stuck in the base of your y horns.

 

[boatguya1]

Re: troubleshooting hot manifolds

Hi guys, would I mess anything up if I pulled the thermostat out,reassmbled it and start the motor to see if the problem is the thermostat? I might of damaged it when I was installing it. I would def replace it,not run it like that. What do yall think is that ok to do?

If the thermostat is bad the motor should overheat.

 

[produceguy]

Re: troubleshooting hot manifolds

If the thermostat is bad the motor should overheat.

I thought that to. Ill pull it apart tomorrow and look. thanks guys.

 

[produceguy]

Re: troubleshooting hot manifolds

when you changed the impellor was it complete?
you could see if the water circulating pumps impellor has come detached from the shaft,maybe slipping. .obviously driven via the belts.
flow seems to be the problem and are you sure the risers do not have any blockages.i.e. incorrectly installed gaskets and flapper rubbers stuck in the base of your y horns.

When I changed it I dont see anything wrong with the impellor, it was all their,Im going to pull lower unit also and check it out. Thanks buddy.

 

[produceguy]

Re: troubleshooting hot manifolds

Alright guys pulled the risers and manifolds and were the two mate, were the gasket sits was pretty bad. The water passeges were about 50% plugged on one side and 90% the other. The risers and manifolds look good its just the passeges are plugged. Can I just clean them up really good and reuse?

 

[dingdongs]

Re: troubleshooting hot manifolds

clean out the best you can and see if they leak or are beyond repair.for peace of mind i would be looking to get some new ones in the near future if you plan to have a reliable boat that will not leak water into your chambers and maybe throw a rod!!!!

 

[wingless]

Re: troubleshooting hot manifolds

Clean the gasket mating surfaces, as though they were going to be re-used.

Then, inspect the manifold, the riser and the knuckle to determine the amount of solid wall thickness separating the water passages from the exhaust gas passage.

Replace all parts that do not have sufficient solid wall thickness.

 

[produceguy]

Re: troubleshooting hot manifolds

I cleaned the passages out and then used a pressure nozzle on the end of a hose to wash them out and I feel good about them now. They will def need to be replaced in the future. Ill put her back together and let yall know if it worked.
Thanks again guys.

 

[produceguy]

Re: troubleshooting hot manifolds

Hey guys, Would it be alright to get the risers and manifolds acid washed?