75hp Force Bogging at high RPM

[roscoe]

Re: 75hp Force Bogging at high RPM

Sorry for the bad news.<br />The Coast Guard rating plate was up next to the drivers seat on those boats.<br />You can always contacy Bayliner for a new rating plate.

 

[plaidpotato]

Re: 75hp Force Bogging at high RPM

well, I found, yet another, independant mechanic that has agreed to rebuild the engine for a reasonable fee, we pulled the head cover and could see the top piston was very loos in the cylinder, the other two had some play but no where near what the top one had, he tells me that he's going to bore out all the cylinders and replace with oversized pistons, and it'll be as good as new<br />any opinions or experience on that?

 

[roscoe]

Re: 75hp Force Bogging at high RPM

One guy says its rebuildable, one says it isn't.<br />Makes you wonder.<br />Maybe the first guy just didn't want to mess with it.

 

[imported_LakeRunner]

Re: 75hp Force Bogging at high RPM

Wow, this sounds familiar! I'm glad you caught it before it damaged the crank or threw a rod. That's my dilema!

 

[hamburgerman]

Re: 75hp Force Bogging at high RPM

I once had an older evenrude 70 the rings stuck on top cylinder then cracked out scored the crap out of it I thought it was shot but I was young and poor so I replaced the rings and head gasket and after alot of running in a barrel the rings must have honed the cylinder smooth but I got back all but 5 psi strange but true

 

[imported_LakeRunner]

Re: 75hp Force Bogging at high RPM

We all do crazy things when we are young and foolish. Those old rudes take a lot of punishment and keep coming back for more.

 

[RRitt]

Re: 75hp Force Bogging at high RPM

I don't think pistons are nearly as sensitive as people think. just need to make sure there isn't so much slop that the motor self destructs. After that a good set of rings can work miracles. They may not last as long, but sometimes you're only looking for another year or two anyway.

 

[klsand]

Re: 75hp Force Bogging at high RPM

I have a 1998, 75 Force, which does the same thing. I have 133 psi on all three cyl.<br />Checked timing, plugs, cleaned carb. and now sprayed the deep creep. Seemed to help a little.<br />I'm thinking the problem is in the Reeds.

 

[plaidpotato]

Re: 75hp Force Bogging at high RPM

UPDATE: I picked my boat up from the mechanic yesterday with my fresh rebuild, all 3 new pistons with cylinders bored 20 over.<br />Plan on taking it to the lake this weekend to break it in, the mechanic said he ran it for 30 min at idle on the hose, but I think there's a little more to properly break it in. I know about running double the oil mixture, but what else should I do specifically to properly break in this new rebuild?

 

[plaidpotato]

Re: 75hp Force Bogging at high RPM

No tips on new rebuild breakin?

 

[roscoe]

Re: 75hp Force Bogging at high RPM

Lots of varying opinions on this subject.<br />I like to keep the rpm below 2000 for an hour, varying the speed every few minutes.<br />Then over the next hour or 2, give it 30-50 second bursts up to 3000 rpm. Do this every 4-5 minutes.<br />Then the next hour or 2, bursts up to 4000 rpm.<br />Then the next hour, briefly hit full throttle.<br /><br />Keep a watchful eye for overheating or unusual noises.<br />Occasionally check the head temp with your hand, just to be sure. You should be able to keep your hand on the head for 5 seconds.<br /><br />There, now you have an excuse to spend 5+ hours driving around on the water.

 

[plaidpotato]

Re: 75hp Force Bogging at high RPM

Thanks for the info...also whats the best way to test to make sure the overheat alarm is working properly, I've never heard it go off, but I havent owned the boat very long.