impeller and spedo water inlet

[mrccure]

recently acquired a 1988 Mariner 150. Pee hole sputters originally and then comes on fairly strong after 1-2 minutes. Last outing alarm went on intermittent and noticed no water output, shut down. Let engine cool and had to restart 1/2 hour later for short idle speed burst, alarm went from intermittent to solid tone and manually shut down motor w/in seconds.
For a few seconds there was a pretty clear white smoke from exhaust, I believe this to be vapor. Obviously time to change impeller, should I check for anything else, did I damage anything? A person on the dock had mentioned that his motor will shut down to prevent damage, both times I had shut down manually.

Also noticed that awhile past the water coming from the pee hole was quite hot as a new boat owner please confirm this was a sure indicator of time to change. As I have recently been reading threads, it seems 2 years is normal for change.

Also, original owner mentioned they had hit a sunken water logged tree brance and since that time the spedometer cable seemed to read slower than normal, is there a hole where the water pressure measures speed that can be cleared out?

I also find the motor is slightly difficult to start first thing, once started it starts quite well through rest of day. Is the two stroke oil bad, is the octane level high enough, I usually put in 89-91 octane, any and all suggestions appreciated.

 

[jebeebe]

Re: impeller and spedo water inlet

I can only help you on the speedometer. There is a tiny hole in the front of the lower unit that you will have to poke a drill bit or somthing in and clean out the wood and you will be in ok. Had a merc 150 that did the same thing..............Jerry

 

[Silvertip]

Re: impeller and spedo water inlet

You have an overheat condition and steam from the relief ports is not a good sign. Overheat can be caused by a number of things including the impeller. However a thermostat that's stuck shut or a bypass valve that is not functioning can also cause it. Having run through a sand or mud bank can fill an engine cooling system with sand or mud and obviously affect cooling. Alarms are just that. When it comes on it means the engine needs help -- NOW -- not next week so it is imperative to stop the engine immediately. The issue quickly get worse, not better. You need to replace the impeller and carefully inspect the housing for scratches or damage. Replace the thermostat and bypass valve as well. Follow that with a compression test to veryify you did not damage the engine. If that checks out, then try an on water test. If compression is low on one or more cylinders, you have some engine damage and running the engine will quickly damage it more so repair it while it's still repairable.

 

[mrccure]

Re: impeller and spedo water inlet

finally able to pull the bottom end, the impellar has all 5 sprockets and look to be in very good shape. Blew through the Tell Tale hole and not clogged. Did not run into any sand bar and was the only one driving for the entire time we have had the boat nearly 2 years. Pulled the thermostat on both heads and both were pretty well darkened and had white corrosion areas on them. Noticed the main shaft was pretty black with carbon on the entire length, believe that to be exhaust smoke. it appeared on the impellar that the locking mechanism that goes on the underside may have been spinning on shaft and lock sleeve, rubber tension piece on top did not look to have any wear indications. I have manual coming tommorow or next day to locate the other locations you mentioned.

I also checked the hole for the spedo intake, it looks like a good amount of impact marks but the hole looked open and could blow through the cable to the opening and have decent air flow through.

There were no signs of any metal in the gear oil nor any water and the oil did not look to be showing signs of severe heat

A side note, after the first time I let cool for hour or so, (started to troll back to dock) and had to restart motor (life safety thing) the alarm went off immediately when started, needed to get to other side of channel, large boats in area, I can only assume the solid sounder from intermittent to be a indicator of extreme temp? The small motor manual cards say it could be an oil sender issue, but with no telltale water, I would not suspect that yet.

Thanks for the quick response with ideas, any additional will be greatly appreciated and checked.

Thank you all soo much for the help.

 

[mrccure]

Re: impeller and spedo water inlet

finally able to pull the bottom end, the impellar has all 5 sprockets and look to be in very good shape. Blew through the Tell Tale hole and not clogged. Did not run into any sand bar and was the only one driving for the entire time we have had the boat nearly 2 years. Pulled the thermostat on both heads and both were pretty well darkened and had white corrosion areas on them. Noticed the main shaft was pretty black with carbon on the entire length, believe that to be exhaust smoke. it appeared on the impellar that the locking mechanism that goes on the underside may have been spinning on shaft and lock sleeve meaning the impellar spinning over shaft and lock, rubber tension piece on top did not look to have any wear indications. I have manual coming tommorow or next day to locate the other locations you mentioned.

I also checked the hole for the spedo intake, it looks like a good amount of impact marks but the hole looked open and could blow through the cable to the opening and have decent air flow through.

There were no signs of any metal in the gear oil nor any water and the oil did not look to be showing signs of severe heat

A side note, after the first time I let cool for hour or so, (started to troll back to dock) and had to restart motor (life safety thing) the alarm went off immediately when started, needed to get to other side of channel, large boats in area, I can only assume the solid sounder from intermittent to be a indicator of extreme temp? The small motor manual cards say it could be an oil sender issue, but with no telltale water, I would not suspect that yet.

Thanks for the quick response with ideas, any additional will be greatly appreciated and checked.

Thank you all soo much for the help.