150 Blackmax overheating

[Iceman66]

Got a problem ,the overheat alarm sounds immediately when engine passes 3000 rpm.
Back to idle, alarm turns off almost at once.
Strong and good tell tale but a bit hot I guess,impeller 4 months old.
Suspect poppet valve, I have the "old " design with the small cover.

Anyone that can tell the part nr on the poppet valve kit I need?

When I bought the engine I noticed that the tell tale pressure vary from strong to less strong when Idling, depending on therm`s opening or closeing I guess.
Now the tell tale is very strong all the time at idling.
As long as I have had the engine there has never come any water out with the exhaus from the two exhausholes above the water.

Should it?

Need some advice here!

 

[wired247]

Black Max 150 means pretty much nothing. Whats your serial number?

 

[Iceman66]

Doesnt have the serial nr right now, but its a 1987 or 88 with carbs,
will try to get the serial nr tomorrow

 

[Iceman66]

Anyone here?

 

[Dukedog]

Sometimes a real good cleaning will work with tha poppet as long as parts arn't damaged. Not so much with tha T-stats which need ta be checked.
Sometimes "just an impeller" change won't last long either. It needs ta have tha complete "kit". Needs ta be OEM. Even if tha stainless stuff "looks" ta be good, it still wears.
You have what's called "Design One" type poppet. Ya might go to ProMarine website for tha kit. Most parts counter guys don't know their butts from a jelly donut without a serial number .Chanches are tha kit will only have tha 4 hole gaskets so don't panic. Just cut tha access off after ya get it together Look for it (serial number) stamped on tha welsh plug, looks like a freeze plug, on top of tha block. It might be there if your one of tha lucky ones......

 

[Iceman66]

Thanks Dukedog! I will start with checking the poppet parts,and see the parts condition.
Understanding you right,I can use the new design poppet kit and remove rest of the gasket when mounted.

What about the "water out of the exhaus hole above water" issue I mention in thread start?

 

[Dukedog]

No. Sayin' that tha gaskets ya get in tha kit may/may not be tha 2 hole gaskets. Don't know. You can buy tha gaskets by themselves. Haven't had a two hole "kit" in years. Tha parts for tha different poppets show ta be different part numbers so they may/ may not actually be a completely different part. Haven't ever compared Design I ta Design II parts.

If all is workin' as it should ya should get at least a "mist" outta tha two slots. You may have a carbon build up that is effectin' that part of it. As long as tha motor is runnin' at right temps with good pressure and stream at temp it should be ok. Its just something that is supposed ta kinda cool tha can. Have seen more than one that didn't have tha mist.......

 

[Dukedog]

No. Sayin' that tha gaskets ya get in tha kit may/may not be tha 2 hole gaskets. Don't know. You can buy tha gaskets by themselves. Haven't had a two hole "kit" in years. Tha parts for tha different poppets show ta be different part numbers so they may/ may not actually be a completely different part. Haven't ever compared Design I ta Design II parts.

If all is workin' as it should ya should get at least a "mist" outta tha two slots. You may have a carbon build up that is effectin' that part of it. As long as tha motor is runnin' at right temps with good pressure and stream at temp it should be ok. Its just something that is supposed ta kinda cool tha can.

 

[Iceman66]

Ok, poppet valve parts difference noticed. Got the Serial no:0A959718 or 0A969718

Went to my boat,let it ran some minutes at idle,seems like the head at port side is a good bit warmer then the starboard side. Normal?

Have just taken the poppet and stats out, poppet and its parts look very clean and good , some salt and dirt at the stats, tested them in a
can with boiling water, the one at port side seems going a bit slow,cleaned it and moves much better.

Will run for a ride later today after reassemble the parts, will let you know what happens.

 

[Iceman66]

Good news!
Mounted all toghether. Ran it at idle about ten minutes,now the tempature is the same at both heads.
Left harbour and ran at from 3000 rpm to wot for a while,no alarm,both heads still same tempature,warm but no problem keepin my hands on them.

Lets hope it stays that way.

Thanks!

 

[Iceman66]

Bad news!
Took it for a ride today, and overheat alarm is back again, when passing 3000 rpm.
Notice that the exhaus smoke is a bit white,
Engine also coughs a little bit when starting up and the first 10-20 seconds at idle.
There is also some hesitating during acceleration before it takes off.
Could I have a leak on one of the heads or maybe between the exaust cover,divider plate and their gaskets.

Will appreciate a lot some more good advice about how to fix this problem.

 

[Dukedog]

Good news! Ya outta know what's wrong with it now...............

 

[Iceman66]

Any trick to determine if the leak it`s on one of the heads or on the divider plate?

 

[Dukedog]

Leak?

 

[Iceman66]

Now I am a little confused,you wrote "Good news! Ya outta know what's wrong with it now" and "leak?"

Sorry for being a bit slow here, but what do you mean I should do now?

 

[Dukedog]

Now I am a little confused,you wrote "Good news! Ya outta know what's wrong with it now" and leak

Sorry for being a bit slow here, but what do you mean I should do now?

Good news means that ya now know which parts NEED REPLACIN'. Ya cleaned 'em all up and it worked for a little while. Replace 'em with new this time.....

Read yours wrong 'bout tha leak. Thought ya ment "ya actually had a leak show this time".........So as for tha question "Could I have a leak on one of the heads or maybe between the exaust cover,divider plate and their gaskets" Not likely,,,,.

 

[Dukedog]

Now I am a little confused,you wrote "Good news! Ya outta know what's wrong with it now" and leak

Sorry for being a bit slow here, but what do you mean I should do now?

Good news means that ya now know which parts NEED REPLACIN'. Ya cleaned 'em all up and it worked for a little while. Replace 'em with new this time.....

Read yours wrong 'bout tha leak. Thought ya ment "ya actually had a leak show this time".........So as for tha question "Could I have a leak on one of the heads or maybe between the exaust cover,divider plate and their gaskets" Not likely,,,,.

 

[Dukedog]

This new format sucks. At least on my lap top..................

 

[Iceman66]

Thanks, will change poppet parts and stats, and see what happends,doubt I`ve got a impeller or a water tube issue,got a really good stream on the water.

 

[sam am I]

1) It was over heating.
2) Took stats and poppet out to test.
3) Tested, It ran good/cool.......Must be 1 of 2 or 2 of 2 items from #2 removed causing it to over heat!!
4) Ran/tested it again, It went to s**t/steaming/cough/puked/O.H. alarmed again............A water in cylinder leak now? WTF? Where? How? How to fix this next issue?
5) Putting new stats and poppet in hoping this fixes item 4? Impeller? Hmmmm, probably not.

Are you sure it is REALLY over temp? Understood the alarm, but you know electronics, it can be flaky. Things to do.......Get cylinder PSI readings, Get the (new?) parts back in, perhaps install a H20 pressure gauge in the mean time(Concur w Duke, low H20 at higher RPM's, not good!! Impeller? Mouse? Grates/Screens? Tartar/Plaque? ), if the alarm goes off again, second source temp measurements, some steam is normal. One step at a time