First time boat buyer overheating/ not running

Kevstar1212

Cadet
Joined
Jul 14, 2019
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12
Okay guys sorry in advance this is gonna be a long post but I’ve done a fair amount of research on your forums and tried to rule out a lot of stuff before making a post of my own. So I’ll try to be thorough with my situation. Been reading a lot on here and it seems you have a good group of guys who are very knowledgeable.

Bought a 1979 searay 24’ cuddy cabin. Supposedly ready to go, turn key. Fired right up on muffs, sounded good, warmed up and didn’t overheat. Lots of new parts he supposedly replaced because he did a starter on it when he bought it and just went through and replaced all the general things that could go bad, ( water pump, alternator, fuel pump, stat, water separating fuel filter, plugs, wires updated to electronic ignition. He didn’t have current tags on it and I didn’t take it out on the water and test it. Looking back, I’ll never buy another boat without running it on the water. I learned my lesson.

1st attempt

on Lake Erie. Started at boat ramp, idled out through to the lake fine ( about 10 minutes of no wake) temp looked good, ran fine, got to lake and my neighbor was driving ( brought him along as I’ve never boated on Erie Myself and he has a boat and been fishing Erie for 52 years. Anyway we got up on plane and went out about 2 miles and relaized we forgot something in the truck turned back and as we were heading back it started loosing rpm eventually stalled out. If started back up but only ran briefly and then died and kept getting shorter time running. Tried changing fuel water serperater and it wouldn’t fill it back up. Towed in, went home pulled fuel line stuck in gas can and it fired right up. Had hard time trying to suck fuel from tank, replaced check valve and fuel line, put back together and it fired right up and ran.

Second attempt.

Launched , idled fine, got on lake , got on plane went about 4 miles out, stopped and started idling in gear setting up poles playing with fish finder. Idled about 5-10 minutes or so and it stalled out. Tried restarting and it ran and then died again, it would start with heavy throttle and stay running with lots of throttle and but if I went to neutral and tried to go in gear it stalled. Noticed this time that the gauge was reading hot and jumping around a lot wasn’t sure if gauge was even accurate. . Thought maybe it was just from running and stalling out and not cooling and engine getting heat soaked. Got towed back once again.

Third attempt.
Launched boat, idled out to Erie went out and payed close attention to temp, temp rose and started jumping around every time I put a load on the boat and rose Very quickly. It got to the red ( doesn’t have numbers just yellow, green and red) and I backed off and idled , got back into channel and it stalled out and I used a electric trolling motor to get back to the boat ramp.



Fourth attempt.
I replaced t stat and ignition coil. Also brought along a IR temp gun and a kid out who is a pretty good backyard mechanic and his family has a boat. Was thinking something was wrong and loosing spark or carb cutting out when warm. Gauge jumped around a lot and wanted to take actual temp reading to verify if motor was running hot or if just bad gauge. Went out and ran it idling around in channel leading to lake because it was 3-5’ waves on lake and I didn’t wanna get stuck stalled out on lake in big waves. Ran boat for 2 hrs idling and taking off in channel and still couldn’t get it to stall. Every time I gave it much more than idle the temp started climbing. Finally I went into channel and circled around around 2k- 2500 rpm let it get up to the red and came in and the temp dropped. We had hard time getting good readings but when temp gauge was up near red we had around 160 on intake near the temp sensor and 140 on hoses leading to elbows and 190 on hoses from manifolds. Went back out let it get up to the red again and came back in and idled and it didn’t cool down quick like last time. Seemed to slowly drop as we idled around and then it stalled out. We quickly changed out ignition coil which temped out at about 170* and it started right up and got us back to the dock. Decided I def had a overheat problem which was leading to the stall out.

Fifth attempt

changed out impeller which didn’t look bad, but was due to replace anyway. Took whole lower unit to marina and had them look at it. They said housing was fine just replace impeller. Did that and took out on local lake, idled around and put under load and it started climbing again. And didn’t seem to cool down quick. Ended up going back to trailer. Never stalled out though.

Got home and Removed a exhaust elbow and opened up cover on end of manifold both looked pretty good, manifold looked pretty good no major flakes on inside of it. Exhaust riser was a little crudded up and had a little bit of rust scale settled on gasket but seemed to have plenty of flow. Checked hose feeding water from impeller and it filled half a 5 gal bucket in 30 seconds. Put back together and then removed the stat on advice of marina and see if extra flow would change anything. Put prop in a garbage can and ran about two minutes. Manifolds and hoses to them got very warm but hoses to elbows didn’t. I was wondering if exhaust was back-feeding from the elbows into cooking hoses.

Marina suggested replacing hoses with clear tubes to monitor flow. I did and had lots of air and almost no flow of water. All hoses had water on both ends and air in the middle. And the had big bubbles slowly come from the stat housing.


Im at a loss. I’m leaning towards heads or gaskets but I feel like there’s still some stones left un turned in the cooling system. Would bad heads or gaskets completely stop the flow of water ? Weird thing is I swear that even when I wasn’t seeing water move in the hoses I though I still had water coming out around the bellows. I don’t get any water coming out the prob when running on muffs. I can tell overheat is getting worse but just not sure what else to check.
With cooling system before really looking hard into heads and gaskets.

Thanks again if anybody actually read this whole post but I didn’t want To waste the time of a bunch of guys telling me things I’ve already tried.
 

Kevstar1212

Cadet
Joined
Jul 14, 2019
Messages
12
Sorry I forgot to include all the boat Info. It’s powered by a merc 260. 5.7 350 sbc and I believe it has a pre Alpha outdrive.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,802
Your last test shows something...if you get bubbles from the thermostat housing esp if you removed the thermostat (this makes it easier to see the bubbles) that suggests a blown head gasket allowing exhaust gas to get into the cooling water. Check for water in the cyls by disabling the ignition removing the spark plugs and cranking it over. Did any water come out of the plug holes?
I had the blown head gaskets and both bubbles from the manifold feed hoses off the thermostat housing and water in 2 cyls.
 

Kevstar1212

Cadet
Joined
Jul 14, 2019
Messages
12
Lou , did you have any signs of water in your oil ? I assumed that if I was getting water in any of the cylinders that would mean hydro lock or major damage. I guess I’ll try pulling all plugs and looks for any signs of water.
 

Kevstar1212

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Joined
Jul 14, 2019
Messages
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I had the blown head gaskets and both bubbles from the manifold feed hoses off the thermostat housing and water in 2 cyls.

When doing this did you still have good cooling flow just with bubbles in it ? Mine seems to have big air pockets and some bubbles coming from the stat housing but not a flow of water with bubbles in it. I was thinking about replacing my intake line from the oil cooler with clear hose and just make sure I was getting good flow and no bubbles feeding it.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,802
Yep I had water in the oil for sure. I rigged this up to test for combustion gas getting into the cooling water...removed the t-stat and could only run it briefly because I used the feed hoses from the manifolds but you can see it as soon as I shut off the engine at the end of the vid...bubbles in the funnels....


https://www.dropbox.com/s/8lz4p4e7pdrtqr2/summer and fall 2016 232.MOV?dl=0

I wound up doing a top end overhaul with re-man cyl heads, all new Fel Pro gaskets and upgraded the old OMC one piece exhaust the center riser Volvo Penta style. The blown HGs were from a bad overheat 3 seasons before when they blew....

finished product:

https://www.dropbox.com/s/55j6h4dd1u8fv0k/IMG_2273.MOV?dl=0
 

Kevstar1212

Cadet
Joined
Jul 14, 2019
Messages
12
Did you have good coolant flow ? I don’t seem to although everything seems open and should flow. I would have expected to see a good coolant flow but with bubbles in it. But can’t find anything wrong in Copland system.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,802
Yep I did. In fact when I had the problem with the Hgs blowing, what the symptom was turned out to be a reluctance to start, did not think of water in the cyls first because before that it was running just fine. Went on vacation to Charleston, SC and came back and no go. Very reluctant to start and it was always a good starter. Went through ignition, checked carb, then just thought of trying to see how the plugs looked....saw some suspicions rust and orange colored electrodes. Blew out the water and tried it, it ran without overheating but it was missing because it was still getting water in a cyl. So tore it down, found blown hgs, and then put it back together with reman heads (originals were cracked in the center cyls exhaust seats due to overheat) etc.
 

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Kevstar1212

Cadet
Joined
Jul 14, 2019
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See I’m reluctant to believe it’s headgaskets or heads without seeing water coming out from them or go into oil. Is there anyway else to explain air in cooling lines other than head gaskets ? It doesn’t even seem like I’m getting a good flow of water. But everything seems to be open and working as it should.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Sorry I forgot to include all the boat Info. It’s powered by a merc 260. 5.7 350 sbc and I believe it has a pre Alpha outdrive.

No such thing as a 'pre-alpha' drive. Merc never made a drive called 'pre-alpha'. As for drives 'before the Alpha One', there's no less then 15 of them... Any idea which 'pre-alpha' you have? (a year on the engine would be a good start too.)

Here's a little light reading for you....

https://forums.iboats.com/forum/eng...e-needs-help-to-go-down?p=6335860#post6335860

and

https://forums.iboats.com/forum/eng...utdrives/10596184-what-is-a-‘pre-alpha’-drive

Chris........
 

Kevstar1212

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Joined
Jul 14, 2019
Messages
12
No such thing as a 'pre-alpha' drive. Merc never made a drive called 'pre-alpha'. As for drives 'before the Alpha One', there's no less then 15 of them... Any idea which 'pre-alpha' you have? (a year on the engine would be a good start too.)

Here's a little light reading for you....

https://forums.iboats.com/forum/eng...e-needs-help-to-go-down?p=6335860#post6335860

and

https://forums.iboats.com/forum/eng...utdrives/10596184-what-is-a-‘pre-alpha’-drive

Chris........

Thanks ! I just know the guy at the marina and the a salvage guy I bought parts from referred to mine as pre alpha and maybe once a MR ? I think. Year of boat is 79 and serial tag on motor I believe is 5178202, it’s a little hard to read. Pretty confident on all number except second to last.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
1979 and that engine serial number place it in the range of 'Mercruiser-1 drive' (MC-1 for short).... People who refer to them as pre-alpha are just showing they ignorance of the proper terminology, and I tend to trust what they say a little less if they don't really know what they are talking about. If they can't get something simple, like the proper term for what they are talking about right?????

Just saying....

Chris...
 

Kevstar1212

Cadet
Joined
Jul 14, 2019
Messages
12
Okay might have made a breakthrough. Took and replaced the hoses going into the riser with clear tubing. Getting lots of air bubbles coming from stat housing. Was thinking gaskets but it’s a ton of air for still running pretty decent. Then I took line off that feeds the system from the impeller and it’s got tons of air in it ? I would assume this is not normal. Any guess how I would be getting a bunch of air in my line coming from there ? Took a good video but it doesn’t seem to be loading. Now sure how to post it. Thanks guys !
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
.... Then I took line off that feeds the system from the impeller and it’s got tons of air in it ? I would assume this is not normal. Any guess how I would be getting a bunch of air in my line coming from there ? ...

Water pump not set up properly, or (and this is the most likely, unfortunately) Water pocket cover has seen too much heat and distorted, allowing exhaust gasses in....

Have a read here.... -> https://forums.iboats.com/forum/engi...55#post5877255

Chris......
 

Kevstar1212

Cadet
Joined
Jul 14, 2019
Messages
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Water pump not set up properly, or (and this is the most likely, unfortunately) Water pocket cover has seen too much heat and distorted, allowing exhaust gasses in....

Have a read here.... -> https://forums.iboats.com/forum/engi...55#post5877255

Chris......

Any good write ups on replacing this water pocket cover ? Do o need to do any more testing before just going ahead and replacing it ? I’m getting lots of air just at idle with the prop submerged In a garbage can.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Certainly pull the drive, do the tests on the water pocket cover. But yes, it sounds like that's the problem. Replacing the cover isn't difficult, apart from bolts being frozen and breaking off. Other than that, it's just 4x 1/4"-20 stainless screws holding it in...

Chris...
 

Kevstar1212

Cadet
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Jul 14, 2019
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So just gotta be careful with getting the bolts out and not snapping them. ? Is there another name for this ? I didn’t see anything in my repair Manila about a water pocket cover. Also is there anything else I should check ? Seems like it shouldn’t leak much air at idle since water pressure should be greater than exhaust gas. I think when I tested it I had it running maybe 1200 rpm. Cause I just stare red it cold and it usually takes a minute to clear up and run at idle good. Thanks
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Which manual do you have? (I can find the page on the water pocket cover for you)...
 

Kevstar1212

Cadet
Joined
Jul 14, 2019
Messages
12
Okay I pulled the outdrive the water pocket cover screws were not very tight. I pulled cover and cover had very slight bow to it. I would say it was practically flat but it was slightly bowed. I also found that the oil seal was damaged around the the driveshaft that goes from the lower unit to the upper. So I took it in to the local marina and asked them to press the new seal in. He also installed the new water pocket cover and seal and assembled the upper and lower unit and pressure tested them. I put the outdrive back on with new gasket and o ring around the water line and filled it with oil. Started it up and I’m still getting air in the line from the impeller!!!! It seemed better after a minute of so of running and I thought I had the air out but then it seemed to get worse again and be pretty much like it was before. I have the outdrive submerged. I’m stumped ! Where could this air come from ? Got a video of it so you can see how much air I’m talking about. Please help a poor guy out and get on the water ! Thanks https://youtu.be/p_08apILE8o
 
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