1988 175 black max cooling problem?

[fastmike22]

I have an 18' bass boat with an 1988 175 black max on it. I'm trying to trouble shoot something. I bought the boat used and have had it for two years now. Engine seems to look like it has low hours by appearance under hood. I had a new water pump put in last year new thermostats and spark plugs. My question is the boat always starts, idles and runs fine. I can idle all day without it getting to hot. Once I put the boat on a plain and get 3/4-full throttle my temp gauge climbs very fast, soon as I get back to 1/2 throttle it drops just as fast. I believe it shows around 180-200 at wide open. I don't get an alarm. Not sure if I'm paranoid or I have a problem. I just don't think I could run it hard for 10 min or it would sound the alarm, never tried. I did just replace the poppet valve this winter but haven't had a chance to take the boat out. Any other ideas?

 

[Chris1956]

Re: 1988 175 black max cooling problem?

well, if it still acts up after the new poppet valve is installed, you have some sort of an issue. Is it possible the motor is mounted high enough that is sucks air instead of water, when on plane? If that is not it, take compression test and look for bad head gaskets.

 

[Dukedog]

Re: 1988 175 black max cooling problem?

Get yourself a water pressure gauge. Check tha head temp with a heat gun. Head temp gauges aren't known ta be real accurate. Sometimes a water pump that sits for any length of time will give up pretty quick. Especially after markets. Water pump kit is tha very first thing ya do when ya get any kinda over heat problem in my book.........jmo

 

[fastmike22]

Re: 1988 175 black max cooling problem?

I have a pressure gauge on the boat. I don't know what kind of pressure I should have a idle, mid throttle or wide open. The temp has climbed like that even after the new impeller kit last year. When I first bought the boat as soon as I got into the throttle the heat alarm would sound so I took it for an impeller change and never heard the alarm again. I figured I would try the new poppet and go from there. Just trying to see what to do next if it isn't the poppet. For some reason I don't think the pressure gauge showed a lot of pressure. Maybe 10 or 12 psi when into the throttle? Cant remember.

 

[wired247]

Re: 1988 175 black max cooling problem?

Most I ever get is around 12-13 PSI WOT . 5 lbs at idle or so.

 

[Dukedog]

Re: 1988 175 black max cooling problem?

I bought the boat used and have had it for two years now.

First thing shoulda asked. Has it been this way since you've had it or just started?

 

[fastmike22]

Re: 1988 175 black max cooling problem?

When I first purchased the boat it didn't have a water temp gauge on it. So I hooked one up using the location on the head. It has done this since I put the new gauge in and after the new impeller and t-stats last year. It usually seems to run cool according to the gauge and I never get an alarm but I usually only run the boat from fishing spot to spot. Probably no more than 5-7 min at mid to upper throttle. Just seems like after a minute or so in the upper rpms the temp rises very fast and cools very fast when I let off the throttle. So yes it has done this since I have owned it just didn't notice it till I put in the gauge

 

[wired247]

Re: 1988 175 black max cooling problem?

Stop looking at the gauge.

 

[fastmike22]

Re: 1988 175 black max cooling problem?

I hope your right. Was thinking of trying those melting sticks on the engine I heard someone talking about. Do you guys know what they are called or where to get them? Once the snow melts here i'm going take the boat out and run it and get a good pressure and temp reading.

 

[racerone]

Re: 1988 175 black max cooling problem?

-----Temple stick ---Is one name I believe.-----There are also stickers with 3 dots on them-----These dots change colour once a particular temperature value is reached.-------Available in many ranges too.

 

[fastmike22]

Re: 1988 175 black max cooling problem?

I know this is old but I was looking for some help. Over the winter I replaced the poppet valve to see if that would cure the problem. I had it out for the first time today. Since the new poppet valve the engine is getting hot quick at just over idle.Water is still cold here. Actually had the temp alarm go off. When I received the poppet in the mail I remember I had to use old and new parts because something in the kit was different, even though it was suppose to be for my engine. I did watch the water pressure gauge and this is what I got.
idle 8-10 psi
just over idle 10-20 psi but it would go to 20 then drop to 10 then back to 20 over and over(Think that was the poppet opening to early?)
Seemed to really go up with rpms but I didn't run it long at all once the alarm sounded
temp gauge climbed to around 220
Had a strong tale of water flowing out the pee hole also

 

[Dukedog]

Re: 1988 175 black max cooling problem?

When I received the poppet in the mail I remember I had to use old and new parts because something in the kit was different, even though it was suppose to be for my engine.

Mistake! There are three different types for tha '88. Design I, II, and III. I and II use two bolts for attaching and III uses four. Ya gotta make sure ta order tha right one. It makes a difference...........Have you installed poppet stuff before or is it your first time ta do so?

 

[fastmike22]

Re: 1988 175 black max cooling problem?

It was my first time. My poppet cover only has two bolts where I do remember seeing the more common one was 4 bolts and peanut shaped if I remember correctly. I just stuck the old parts back in to give them a try. I think maybe I never had a problem to begin with just got a little paranoid when the temp was rising on the gauge in the upper rpms. But I never got an alarm