motor getting warm?

[Divecaptchris]

Ok so i went out for a cruise on my 1983 carver 28' mariner. One motor needs replaced and one runs good, well at 1400rpms and lower she runs at 180, at 1600 she will sit somewhere around 190-200, above that she gets hotter! didnt go there for long as soon as she went over 200 i brought the rpms back down, temp came back down. so is this because its such a big boat running on one motor? a mechanic told me that however I have a hard time beliving it. The water pumps were just replaced, the mechanic said he wasnt happy with the water flow from the thru hull connection, i went under the boat and the cover over the pickup was not clogged, is there a way to remove that cover and see insde? any other ideas?? I need to bring the boat back to my house, about a 60 mile trip, I plan to run it at hull speed, about 14-1500 rpms(6-7mph) to conserver gas and not put too much stress on the one good motor. Will I cause a prob at that rpm if the temp stays at 180??

 

[EddiePetty]

Re: motor getting warm?

....sounds like an exhaust restriction to me!!!

Thime to check risers, flappers (shutters) hung in the exhaust or other obstructions.

 

[EddiePetty]

Re: motor getting warm?

....sounds like an exhaust restriction to me!!!

Thime to check risers, flappers (shutters) hung in the exhaust or other obstructions.

Edit: A clue as to the type cooling system would be helpfull!!

 

[Bondo]

Re: motor getting warm?

on my 1983 carver 28' mariner.

Ayuh,... We don't care what yer boat is,.... What are the Motors,..?? What are the Drives,..??

 

[Divecaptchris]

Re: motor getting warm?

305's with v drives

 

[Divecaptchris]

Re: motor getting warm?

....sounds like an exhaust restriction to me!!!

Thime to check risers, flappers (shutters) hung in the exhaust or other obstructions.

Edit: A clue as to the type cooling system would be helpfull!!

Manifolds, risers, elbows and tees are all brand new!

 

[EddiePetty]

Re: motor getting warm?

Manifolds, risers, elbows and tees are all brand new!

...that's nice to know,but, any of those new components can be blocked by debris, left-over impeller pieces or destroyed flappers!!!

Open or closed cooling system?

 

[EddiePetty]

Re: motor getting warm?

"One motor needs replaced and one runs good, well at 1400rpms and lower she runs at 180, at 1600 she will sit somewhere around 190-200, above that she gets hotter! didnt go there for long as soon as she went over 200 i brought the rpms back down, temp came back down. so is this because its such a big boat running on one motor? a mechanic told me that however I have a hard time beliving it."

....doing some re-reading here.

Am I to understand that the "One motor needs replaced" implies that that particular engine was NOT running when the overheating issue arose on the "good" engine?????

If so, I'm gonna start leaning towards your mechanic's opinion.
With such a large/heavy craft being propelled by the single, off-center prop, I'm inclined to believe the prop is probably loosing grip as you increase engine speed, producing extreme ventilation/cavitation and thus aerating the supply water to the impeller.

 

[Divecaptchris]

Re: motor getting warm?

yes i am running only on the port motor. The pickup is forward of prop shaft, could it do that? I did notice a feeling of cavitation when i tried to go over 1800rpm. If so do you think I will hurt the motor running it at 1400 for 60 miles over 2 days? of course making sure the temp stays atg 180 deg

 

[EddiePetty]

Re: motor getting warm?

yes i am running only on the port motor. The pickup is forward of prop shaft, could it do that? I did notice a feeling of cavitation when i tried to go over 1800rpm. If so do you think I will hurt the motor running it at 1400 for 60 miles over 2 days? of course making sure the temp stays atg 180 deg

Gosh!!! I RE-re-read your original post and am just now having the Vee drive thing set in!!!!

(Ya' know, ya' work on outdrives so much you get to thinking that that's all there is out there!!!!)

I still think it's either an obstruction in the exhaust or aerated cooling water.

Now, from personal experience, I nursed a 3.7 about twelve miles at 1K r.p.m.s with a blown impeller pump relying on just natural convection to cool the engine via the heat exchanger (closed cooling system).
IF you can maintain a temperature of no more than 180 over your intended course, I can see no harm in completing your journey. As a precaution, if you have a closed cooling system, dump the antifreeze mixture and replace with WaterWetter and freshwaterfor the duration of your voyage.
(sorry for overlooking the vee-drive)

 

[Divecaptchris]

Re: motor getting warm?

Does anyone know how the cover over the intake on the hull is removed? Can i do it while it is in the water? a drawing would be awsome if anyone has seen one on the net! I have a feeling there is growth inside there!

 

[Divecaptchris]

Re: motor getting warm?

Gosh!!! I RE-re-read your original post and am just now having the Vee drive thing set in!!!!

(Ya' know, ya' work on outdrives so much you get to thinking that that's all there is out there!!!!)

Yeah I have had outdrives on my last three boats, havin a hard time convertin myself!