Bogs down in mid-range but using extra oil for break-in

[Reggie08]

I'm in the break-in period on my 85' Rude 90hp so I'm using a 25:1 mix (recommended since I'm not using the VRO tank) Ever since adding the extra oil, it seems to not want to run well in the mid-range for power (half to 2/3 throttle). I initially thought it was a spark problem, but checked for spark on all 4 cylinders and it's good. So I thought it was the 115hp high speed jets I installed (over-sized cylinders) and maybe it was getting too much fuel, but put the 90hp jets back in with the same results.

If I stay into the throttle, it eventually comes out of it then seems to run pretty good. The very first trip we took with the motor though, I was using 50:1 and it didn't have this problem.

Is the added oil causing the motor to want to bog down a bit? Or is there something I need to check? Carbs are cleaned and the floats are set properly. Did a lync-n-sync (though I may re-check it) and set the WOT timing per J.Reeves' method in the FAQ's. Everything looks good, just seems to not want to run like it did the first time.

 

[kenmyfam]

Re: Bogs down in mid-range but using extra oil for break-in

Are the carbs clean and O.K. ????

 

[Reggie08]

Re: Bogs down in mid-range but using extra oil for break-in

Yep! The guy I got the motor from had cleaned them real good prior to replacing them with 140hp carbs but to be safe, I took them apart, checked the float, checked/cleaned the high-speed jets, replaced the gaskets and cleaned out all the orifices.

 

[kenmyfam]

Re: Bogs down in mid-range but using extra oil for break-in

Are you sure you have not got too much oil in ??

 

[Reggie08]

Re: Bogs down in mid-range but using extra oil for break-in

Because higher math eludes me, can someone double check my mixture?

I bought some Pennzoil Synthetic Blend TCW-3. The bottle said for a 50:1 mixture, use 16oz per 6 gallons of gas. Since I want a 25:1 mixture, I used 32oz per 6 gallons gas. And since I have a 12gal tank, that meant using 2 full 32oz bottles.

 

[Reggie08]

Re: Bogs down in mid-range but using extra oil for break-in

Sorry Kenmyfam, you posted just as I did. My above post is the mixture I used but like I said, higher math eludes me at times.

 

[kenmyfam]

Re: Bogs down in mid-range but using extra oil for break-in

Bottom line for a 25 to 1 mixture is 25fl oz gas to 1fl oz oil.
Now I am originally from England where we have 20 fl oz to a pint. I believe that in the U.S.A it is 16 fl oz to a pint ???
Therefore I measure the way I stated at the start.
English gallon = 4.45 litres
U.S. gallon = 3.85 litres (I think ????)
Correct me if I am wrong.

 

[Reggie08]

Re: Bogs down in mid-range but using extra oil for break-in

You're guess is as good as mine

I think what I may try is a 32:1 mixture next time we go out and see if that changes anything.

 

[kenmyfam]

Re: Bogs down in mid-range but using extra oil for break-in

How long did you run at the "25 to 1" ratio ???

 

[Reggie08]

Re: Bogs down in mid-range but using extra oil for break-in

This was our first trip with the 25:1 ratio. It was our second trip total with the motor. Our first trip was a couple of weeks ago and I used a 50:1 ratio then with no problems from the motor.

 

[reeldutch]

Re: Bogs down in mid-range but using extra oil for break-in

i dont think 25:1 will make your motor bogg down.

you say you set the timing per Mr reeves static method.
You set the timing initialy like that but you should verify it with the motor running.

i think your timing could be off.

double check the timing and link and sync

and also check your plugs for fouling.
if you have good top end your fuel pump should be ok.
if its mid range

 

[Reggie08]

Re: Bogs down in mid-range but using extra oil for break-in

I initially thought it was a timing issue as well but I didn't check the timing until after it started bogging down. Nor did I change anything. It was reading 24 degrees using J.Reeves' post so I left it alone. Plus I'm still in the Break-in period so I'm not supposed to run WOT per the manual. Should I go ahead and set the timing with the boat on the trailer in the water anyways?

I'll probably re-check the lync-n-sync to make sure something didn't go out of whack. I may also replace the plugs to see if that helps as well.

 

[Reggie08]

Re: Bogs down in mid-range but using extra oil for break-in

Quick update.

Broke open both carbs again this morning and found the float in the top carb was misadjusted (it was adjusted to high). I could have sworn I checked that before I put the carbs on the first time. At any rate, I re-adjusted the float so it's level and re-installed. Finished the lync-n-sync and things seemed to run much better. Haven't put it on the water since we have 30mph winds today but hopefully later this week I can take it out to see how it runs.

On a side note, my Faria Tach I thought wasn't going to work, works perfectly (wrong setting). I set my idle at 1100rpms on the muff's but I'll re-adjust as necessary once I get it in the water.

 

[wahoo 16]

Re: Bogs down in mid-range but using extra oil for break-in

let us know how it turns out. i really believe this sounds like intermediate fuel circuit problems , make sure intermediate passages are clear. after we enlarged (drilled) my carb pasage (top of throat behind throttle plate), i havent had any more problem. drove all weekend 8 gallons worth of cruising, no stalling, no bog no problems.

 

[Reggie08]

Re: Bogs down in mid-range but using extra oil for break-in

Yeah I'm real interested to see how it does especially in idle/low speed. A local mechanic here mentioned I would probably have to drill out my high-speed jets a little to compensate for the larger cylinders (3 at .030 and 1 and .040). He said mid to high speed ranges it would run fine but the low speed and idle would, as he put it, "run like a 3-legged dog".

 

[Reggie08]

Re: Bogs down in mid-range but using extra oil for break-in

Another quick update:

After re-adjusting the float in the top carb (it was set too high; bottom carb set just fine), the motor ran real good. No problems throttling up at all. She ran real nice this evening.

Thanks to everyone!