OMC/Volvo Penta Planing issues?

[bruceb58]

Re: OMC/Volvo Penta Planing issues?

Timing by ear? I only do that to get an engine running, then out comes the timing light.

You can set the timing of an engine with a timing light by just cranking the starter. Doesn't even have to be running.

 

[bajaunderground]

Re: OMC/Volvo Penta Planing issues?

You can set the timing of an engine with a timing light by just cranking the starter. Doesn't even have to be running.

bruceb58, never met you, but you're level of expertise is awesome! I would never want to play jeopardy against you (or any trivia game for that matter!) Someday, I will buy you some beers! This forum is hugely in debt to you, and others, for your willingness to impart your expertise and wisdom...:very_drunk:

 

[bruceb58]

Re: OMC/Volvo Penta Planing issues?

I would never want to play jeopardy against you (or any trivia game for that matter!) Someday, I will buy you some beers!

I suck at trivia and jeopardy but I will take the beer!

 

[jerryjerry05]

Re: OMC/Volvo Penta Planing issues?

Timing by ear???
Not the way.
We fired the road guy and I got to replace him and fix all his screwups.
Was sent out to a NEW 26.
After the other guy did the 20hr service.
The customer said after the other guy checked the boat it wouldn't get over 20mph.
I started looking and pulled out my timing light.
The customer said the other guy didn't use one of those?
What's it for??
The timing was set by ear?
It was so far out it was lucky it ran at all.
Re set the timing and showed the owner what the trim switch was for.
35mph.
Got a $50 tip.

 

[MikDee]

Re: OMC/Volvo Penta Planing issues?

bajaunderground, I thought you said your WOT RPM's were between 4200-4600? I didn't realize that you meant this was the recommended RPM for your engine, and you can really only get to 3700RPM from your boat now. So, IMO, you have an engine problem, not a prop or hydrofoil problem.

 

[bajaunderground]

Re: OMC/Volvo Penta Planing issues?

bajaunderground, I thought you said your WOT RPM's were between 4200-4600? I didn't realize that you meant this was the recommended RPM for your engine, and you can really only get to 3700RPM from your boat now. So, IMO, you have an engine problem, not a prop or hydrofoil problem.

Yes, that is correct my recommended WOT rpm's are the 4,200-4,600 and I got the 3,700rpm the other day.

Jerry, thanks for that, unfortunately there's no one to fire here, just myself...:facepalm: I shall forever be banished into the netherworld of bad advice takers and shall not give the advice to set timing by feel nor sound! I would never trust a "professional" mechanic who set timing by ear...I don't know why I thought I could get away with it...I know better...it's just that it sounded very good when I set it and I thought "how hard can it be?"

 

[jeffnick]

Re: OMC/Volvo Penta Planing issues?

Check the throttle opening. Put the handle at wide open and see what the butterfly looks like. Normally you don't adjust idle by messing with the linkage.

 

[MikDee]

Re: OMC/Volvo Penta Planing issues?

Yes, that is correct my recommended WOT rpm's are the 4,200-4,600 and I got the 3,700rpm the other day.

Jerry, thanks for that, unfortunately there's no one to fire here, just myself...:facepalm: I shall forever be banished into the netherworld of bad advice takers and shall not give the advice to set timing by feel nor sound! I would never trust a "professional" mechanic who set timing by ear...I don't know why I thought I could get away with it...I know better...it's just that it sounded very good when I set it and I thought "how hard can it be?"

Don't feel so bad, and knock yourself out over it, we've all done dumb things in the past, then got old, & wise,,, Or, just got Old!

When I first started driving, ages ago,,,lol, I had a 2dr 57"Chevy stick 6. I used to goto the gas station, and get Sunoco 260 hi octane gas, then loosen up my distributor, and advance it by ear, until it would run rough, then back off a little, then road test it, and if it pinged, I retarded it just enough so the ping was gone, then tightened it down, & ran it with that tank of gas. Afterwards, I'd put a timing light on it to set it back to specs.

 

[bajaunderground]

Re: OMC/Volvo Penta Planing issues?

If I remember correctly this model is 5˚ BTDC? It's listed in the riser...so not really a question...just a statement reaffirming.

 

[bajaunderground]

Re: OMC/Volvo Penta Planing issues?

Check the throttle opening. Put the handle at wide open and see what the butterfly looks like. Normally you don't adjust idle by messing with the linkage.

I understand this concept; however, in my case I think the cable was over-long (due to me replacing motor and pulling controls). I think it was pushing against the throttle plate and not allowing it to idle...I just un-hooked at carburetor, let carb linkage return to an "at rest-neutral" position and then adjusted the end of the throttle cable until they aligned., re-connected...I wasn't adjusting the idle per se, I was merely adjusting the throttle cable connection.

 

[4now04]

Re: OMC/Volvo Penta Planing issues?

Make sure you don't have an exhaust flapper valve restricting exhaust. If they are not correctly installed at the top of each side of the Y pipe they may be lodged in the bottom of the Y pipe at the transom. The engine should turn right at 4600 rpm when trimmed out at top end with the original prop size.

Use a timing light. Anything else is a guess.

Buy a 3/8" drive spark plug socket that has a u joint built in. Works great. Leave the manifolds in place.

 

[bajaunderground]

Re: OMC/Volvo Penta Planing issues?

UPDATE: Set timing to 10* BTDC with a timing light...the engine sounded smoother and idled at 650-700rpms which was better than the 500rpms it was idling at. I'll report back next week after another test run!

Thanks Again!

~Brett

 

[bruceb58]

Re: OMC/Volvo Penta Planing issues?

What was it at before?

 

[bajaunderground]

Re: OMC/Volvo Penta Planing issues?

What was it at before?

I believe about 0* TDC; however, I couldn't 100% tell as only the 10* mark was white and what a PITA too see!!

 

[bruceb58]

Re: OMC/Volvo Penta Planing issues?

I believe about 0* TDC; however, I couldn't 100% tell as only the 10* mark was white and what a PITA too see!!

Wow! That is WAY off. You should definitely see the difference.

 

[bajaunderground]

Re: OMC/Volvo Penta Planing issues?

So, I have not reported back since the last timing set and run.

So, I adjusted the timing to the requisite 10˚ BTDC, took her out and she planes much faster, but still not the punch I was expecting; however, Was able to hit 39mph via GPS, which is a huge improvement.

what's been done since the second trip...

I replaced cap and rotor, replaced fuel filter, adjusted the linkage on the carburetor...which leads me to my questions...by initially shortening the cable linkage during the motor install, to keep it idling, so to speak.

So today, I adjusted the linkage (about the amount I took in when it wouldn't idle the before setting timing and whatnot as mentioned abpve). The appears to push open the linkage more, but not all the way. It has an electric choke, which somehow connects to a cam, that can adjust the butterflies beyond the throttle linkage. Is it normal (when cold) for the butterflies to open about 80% of the way at WOT when cold (and not running)? Once it warms up, does the choke allow the butterflies to open the rest of the way? I do see "wear" marks in the openings, so I know the butterflies have opened to a 90˚ vertical position previously, just not sure we're getting there now...they open about 70˚ when cold and unstarted. I hope this makes sense...I can clarify if needed?!

Again, just trying to reach the recommended WOT of 4,200-4,600rpm.

Thanks for helping out all!

~Brett

 

[Maclin]

Re: OMC/Volvo Penta Planing issues?

The choke linkage should not affect the butterflies at all. In fact the opposite is usually the case, meaning when the throttle plates are opened to WOT there is a linkage that will open the choke plate some if the choke plate is still closed. I believe that is called a Choke Unloader mechanism and is there for cold starts when flooded.

This is not applicable to your boat but if you have heard of this then I can see why you asked the question, in Carter Thermoquads the secondaries are locked out while the choke is closed on a cold engine, the choke has to be almost all the way open before the secondary linkage is not locked out. A QuadraJet may have a similar feature, not as familiar with those.

 

[alldodge]

Re: OMC/Volvo Penta Planing issues?

Also, any chance it's a throttle connection issue? Meaning, I cannot open the butterflies all the way? The reason I ask is when I intially re-installed the motor she wouldn't stay idling because the throttle cable was pushing too hard against the linkage, so I adjusted it to a neutral position and it idled fine!?

Thanks,

~Brett

I understand this concept; however, in my case I think the cable was over-long (due to me replacing motor and pulling controls). I think it was pushing against the throttle plate and not allowing it to idle...I just un-hooked at carburetor, let carb linkage return to an "at rest-neutral" position and then adjusted the end of the throttle cable until they aligned., re-connected...I wasn't adjusting the idle per se, I was merely adjusting the throttle cable connection.

So, I have not reported back since the last timing set and run.

So, I adjusted the timing to the requisite 10˚ BTDC, took her out and she planes much faster, but still not the punch I was expecting; however, Was able to hit 39mph via GPS, which is a huge improvement.

what's been done since the second trip...

I replaced cap and rotor, replaced fuel filter, adjusted the linkage on the carburetor...which leads me to my questions...by initially shortening the cable linkage during the motor install, to keep it idling, so to speak.

So today, I adjusted the linkage (about the amount I took in when it wouldn't idle the before setting timing and whatnot as mentioned abpve). The appears to push open the linkage more, but not all the way. It has an electric choke, which somehow connects to a cam, that can adjust the butterflies beyond the throttle linkage. Is it normal (when cold) for the butterflies to open about 80% of the way at WOT when cold (and not running)? Once it warms up, does the choke allow the butterflies to open the rest of the way? I do see "wear" marks in the openings, so I know the butterflies have opened to a 90˚ vertical position previously, just not sure we're getting there now...they open about 70˚ when cold and unstarted. I hope this makes sense...I can clarify if needed?!

Again, just trying to reach the recommended WOT of 4,200-4,600rpm.

Thanks for helping out all!

~Brett

From your post above I'm hearing the carb is not opening all the way. If this is not happening then you will not have max WOT. If you cannot get the carb to open all the way without the linkage connected, look at the carb. If it will open all the way without the linkage connected, and will not with it connected look at the cable and linkage.

There is no issue with a cold carb on a non running engine to have the choke not open all the way.

Did you ever run a compression test and if so what was found?

 

[bajaunderground]

Re: OMC/Volvo Penta Planing issues?

From your post above I'm hearing the carb is not opening all the way. If this is not happening then you will not have max WOT. If you cannot get the carb to open all the way without the linkage connected, look at the carb. If it will open all the way without the linkage connected, and will not with it connected look at the cable and linkage.

There is no issue with a cold carb on a non running engine to have the choke not open all the way.I can open them all the way manually, there's no hang up, but when the controls/throttle is all the way forward it's only about 80% open? It's a Holley 2bbl

Did you ever run a compression test and if so what was found?I have not, as that's a pretty involved test...the bottom end and gaskets are all new and I have no reason to believe there's a compression issue. I know it the standard for trouble shooting performance issues...*sigh* I just want to believe it's something much simpler and not gaskets!? Wishful thinking/denial, maybe?

Alldodge (and all), I way appreciate your assistance in this matter, I'm thinking I'll drop her in the local lake today and see what happens? A compression test may be on the horizon? I just have my doubts as everything is more or less new and runs very, very well...except the whole WOT thingy.

~Brett

 

[MikDee]

Re: OMC/Volvo Penta Planing issues?

So, with the engine OFF, and in forward gear, open the throttle fully,,, Then go back by the engine, & look down into the carburetor, and see if the butterfly's are opening all the way? If the choke is in the way, open it manually for now (that would be another issue to check later).