1989 Blackmax compression

[Big Fish Billy]

Re: 1989 Blackmax compression

If it were detonation it would really only do it under load. From someone who has detonated a few motors to death ...you CAN hear it and when you hear it , its too late.

Could be bearings, could be piston slap in a cold bore, could be a worn out piston or bore. rings could just be stuck. Chrome bore motors can have a bad bore or more re sleeved with an iron sleeve and saved.

I still think if it runs OK I'd just let it run if the bearings check out. Try the decarb.

Also could be piston topping out in chamber because of carbon on top...decarb is definitely worth a try....

 

[Larry Tate]

Re: 1989 Blackmax compression

So I did the screwdriver test and there was no play in the rods. Makes me feel a lot better. It had good compression as well so I'm gonna put good gas in it and take it for a ride on Champlain. Will post results

 

[Larry Tate]

Re: 1989 Blackmax compression

Took the boat out earlier today and it was rough. Put good gas in it after decarb and the results were not much better. In gear if you go to hole shot it stalls. Seems uneasy at rpm under 1,200 or so (no tach so just estimating, not an exact rpm). Still had top end power but a shaky low idle doesn't cut it for me. Any suggestions? I heard someone earlier in this thread say something about trigger position. I may try to adjust that. Can someone at least post a part number or link for carb kits and fuel pump kit? Thanks guys, I must say you have been a huge help so far.

 

[Dukedog]

Re: 1989 Blackmax compression

I'll get ya some numbers for Pro Marine stuff in justa bit. Will need ta pm 'em to ya. Site won't let ya post a link to tha competition! iboats kits are wrong.....or at least they look and are listed wrong. I know what Pro Marines sells plus they will have new needle and seat. If ya got a dealer handy any wh (135 ta 225) kit will work. All they usually need is a good cleaning and NEW gaskets, floats set.........Simplest carb ya ever ran across......

Is your pump tha oval or square type?

I wouldn't jack with anything else till ya get these done. Trigger timin' doesn't usually change unless ya replace trigger or turn screws unnecessarily...........jmo

 

[Larry Tate]

Re: 1989 Blackmax compression

Ok gonna order these parts asap, thanks duke. From what i've described do you guys believe it will fix my motor issue? Or do you think it's something else? I heard merc primer bulbs need to be on these motors. Not only is mine not a merc bulb, it's a total piece of crap. How important is it really to put an oem bulb on this?

 

[Larry Tate]

Re: 1989 Blackmax compression

Duke, is that website legit?

 

[Dukedog]

Re: 1989 Blackmax compression

If its got a "knock" then no. Its not gonna go away till you find out what it is. Its gonna be one a few different mechanical parts that's doin' it.
Reason for tha oem bulb is a better chance of it bein' good outta tha box and fewer problems down tha line. But with tha way "most" manufactures are nowdays, any can be sub-standard. Even "Mother Merc". ie: Tha new hot rod hub kit has 5 new pieces all in one new box. Each piece comes from a different country (not USA either). Tells what kinda CENTS they're concerned with huh!

 

[Dukedog]

Re: 1989 Blackmax compression

Duke, is that website legit?

Pro Marine? Yes..........Why do ya asked?

If you can find tha kits "without" needle and seat they will be cheaper.......Just tha "gasket kits" is usually all that's needed but most places (counter guys) need a serial number ta even think 'bout findin. a part although most all tha wh carb "kit" stuff is pretty generic. Think '80 and newer.........Some of tha on-line parts places are a crap-shoot to. ie: iboats with wh carbs.

 

[Larry Tate]

Ok this thing needs batteries bad. Does anyone have a certain make/model to recommend? I don't wanna break the bank but I also don't wanna get a cheap pair of batteries! CCA, stuff like that would help. Thanks guys. Ps my carb kit comes in today will post results.

 

[Larry Tate]

Ok here it goes...Did the carb rebuilds and the fuel pump. Found a few things that seemed off so I felt pretty good that it would fix it. Long story short I was upriver from my boat launch and the thing was running great. Then the overheat beep. Took the cowl off let it cool down...stated it up later and put it in gear to putt back to the launch, and I saw water streaming out from the head gasket seal. A few things: 1. How bad 2 How much Thanks guys for advice.