Almost ready to pull trigger

[t mac]

Hello All. I had a sea trial today on a boat I am interested in. There were some things that I saw that I liked and some things I saw that I disliked. More on the good later. I have not purchased this boat yet and I am not going to unless I can get an idea of what the issue is.

The boat has a 4.3 I/O and it is suspiciously clean. I mean you could eat off of this thing. Once the boat was up to running temp. I noticed that one of the manifold/risers was hotter then the other. Signifigantly so. Like a difference of 40 or 50 degrees. Why would that be? If I need to replace then I will cross that bridge in negotiations. No smell of gas, no ping, no knock, accepted throtle with no issues at first but then it wouldnt rev over 3200 rpms. WOT would only get up to 3200. Moments before that it was stealy cruising WOT at 4800. Why might this be? Any thoughts would be great.

I am slightly mechanically inclined so fixing some things shouldnt be an issue.

Last. I just wanted to tell you all thankis for the warm welcome.

[spareparts]

have it checked out by a sterndrive mechanic(some outboard guys are lost on I/Os), including a compresion test. Those manifolds will feel different, don't know exactly why, but they always do(at least at lower speeds). but it could be an indication of teh manifolds needing replacement($$$$$)

[phatdaddy]

not a lot of experience i/o ,but i know raw water cooled risers are an issue & bellows on the outdrive. did it have a temp guage?

[t mac]

Temp guage read normal. To the best of my knowledge it worked which is to say that it heated with the motor and it stopped at about 170 which is where it stayed.

[nymack66]

It could be a fuel restriction or clog filter who knows? Question is why guess? Please do yourself a huge favor pay a mechanic to ride along with you for a test run, most good honest one will do a pre-inspection for under 150.00.
Any good honest seller will not mind you doing this ...
Good luck and keep us posted...

[phatdaddy]

if that motor is a v6, maybe the water cools one side and then goes to the other, so that is normal. i have very little exp with them. i never was a fan of running hot salt water through a car engine. some body who knows what they're talking about will be along..

[dboyd351]

The cooling passages in the risers can become clogged with rust as they get some age on them. Pulling them and cleaning the rust out may well solve the discrepancy as long as 1) the bolts aren't so rusted to the manifold that you can't get them off and 2) There isn't so much corrosion the risers need replacing.

That might not be what it is, but it sounds like a possible reason for what you are describing.

Having a mechanic check it out, as previously suggested, is certainly a wise decision, too.

[spareparts]

if this is the boat in the for sale section, it has one piece manifolds, the risers are made into it. They are not available any more, it will have to be changed to a two piece manifold/riser set up, not a big deal, just different. As far as the temps of the manifolds, I've had brand new engines run one manifold hotter than the other at lower engine speeds, usually with alpha set ups. The water pump doesn't create enough volume to completly fill each manifold before exiting, the water allways takes the path of less resistance, so one maniofld gets more water than the other. On bravo ste ups, the belt driven pump can flow more water at idle speed to fill to restriction both manifolds and risers. If the manifolds are getting unevenly hotter at high rpms, then there is a restriction. Also consider the age, around here in salt water, if the engine hasn't been flushed, figure manifolds every three to four years, if its been flushed regulary, then figure 6 to 8. The one piece manifolds haven't been around for some while, if you could determine how old the engine iks, it would help. Unless the engine was a new old stock, or the boat has been pickled for a number of years, I'd go ahead and figure on new manifolds and risers. About $800-$900 in parts, plus labor

[Bruce]

pay a mechanic to do a total assessment on the boat. If its a 2 piece riser/manifold setup, pay him to remove the riser to check it out to see if the gaskets indicate any water getting into the engine. This could be money pit waiting to happen, be smart on this.. You seriously do need a compression and leakdown test on this motor as well.. I've seen 4.3s run flawlessly but have the back two cylinders 50psi lower then the rest, thus needing some major work. Also the mechanic will check out the outdrive, bellows, etc, and see if the gearlube has any oil in it. If the bellows fail on this setup the boat sinks, be an informed buyer, Don't skimp now.

[Blue_Runner]

Sounds like you need to find a V20/V21 w/ an outboard....or bare hull & and hang an outboard on the back of it. No offense to the I/O guys!!!