Engine won't reach WOT - on new engine

[aquador]

I have a 22 feet boat with a new Indmar 5.7 carb engine (http://www.barrmarine.net/57l-bobtail-carbureted.html) with a Volvo Penta duoprop sterndrive.
The engine was installed new in 2015 and had numerous problems (extensive list below).

The remaining problem is that the boat will not reach WOT. It works fine when idling, but maxes 3.000 RPM (WOT is 4.600) and the boat will not plane.
The problem surfaced suddenly when drive the boat home after a short stop.

My new boat mechanic claims that it is caused by a faulty power trim pump preventing the sterndrive from being in proper position. Currently, with boat on land, the driver can only move down - no reaction when moving power trim up - perhaps a faulty switch. During last season I sure the drive could be moved up while experiencing the same problem. I have already tested and changed so many parts and am reluctant to do this new 1.000 USD operation.

This is what we have tested:

1. Fuel condition. Type and Octane possibly old fuel
Tested with new fuel and external tank. Also changed to a new fuel filter several times.

2. Propeller pitch or diameter, damaged blades
The boat did previously full WOT and 50 mph with the same propellers

3. Restricted fuel pickup tube or anti siphon valve Fuel System Test
Tried with an external tank and changed to new fuel pump.

4. Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
The engine is new and oil level seem fine.

5. Marine growth on hull and outdrive
No. Swiped the bottom clean and no difference

6. Wrong gear ratio in outdrive
The boat did previously full WOT and 50 mph with the same propellers and stern drive. The drive has been fully renovated by a Volvo Penta authorized dealer

7. Restricted carburetor air intake (clogged flame arrestor)
There is no filter and tried removing the flame arrester and with engine hatch open.
Also change to different new carburator. No difference.

8. Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
New flappers were installed, but upon inspection they sit correctly and moves freely and cannot block.

9. Poor cylinder compression Compression Test
The engine is brand new - less than 50h. A compression test was done on the engine and all were fine.
The tops were removed and pressure tested and all fine. Put back together with new gaskets (by professional)

10. Carburetor defective, or wrong type.
Also change to different new carburator. No difference.

11. Fuel pump pressure and vacuum
Changed to new fuel pump. No difference. Have not measured pressure. Will do when boat is in water again.

12. Boat overloaded, improperly loaded, or improperly trimmed.
The boat did previously full WOT and 50 mph with the same propellers

13. Engine Overheating
A carb engine - no warnings and temp is fine

14. Engine timing and ignition system operation
Have not tested, but new boat mechanic claims it cannot be timing. Will test with a stroboscope when boat is in the water.

15. Remote control cables and linkage for proper travel to open throttle plates fully.
Seems to work fine. Have also tested with pushing the levers directly on the carb. No difference.

I have exhausted friends and family and nearly 2 boat mechanics. I appreciate any help.

THanks
// Jens

 

[Bt Doctur]

No mention of timing , total advance, firing order, sparkplugs, unless its a 305 (210Hp) and not a 350

 

[harleyman1975]

Is throttle opening all the way? Is the timing advancing as it should? Are you absolutely certain the firing order is correct? Cap and Rotor new? Plug wires new?

 

[Scott Danforth]

PM a mod to move to the volvo section.

Does the throttle open all the way?

Is the base timing set properly?

Check the fuel filter contents

 

[alldodge]

9. Poor cylinder compression Compression Test
The engine is brand new - less than 50h. A compression test was done on the engine and all were fine.
The tops were removed and pressure tested and all fine. Put back together with new gaskets (by professional)

Boat running great then looses power and otherwise idles fine. I would like to know what the compression values are, and 100 psi is minimum. I would expect to some at least 140 psi for a new motor.

My guess is timing was not correct and tuliped some valves

 

[jimmbo]

Has the new engine EVER attained the RPM of the old one? 2bbl carb or 4bbl? Is the timing advance mechanical or electronic? Wrong camshaft or cam/crank sync not correct?

 

[aquador]

Do you guys think it has anything to do with the power trim?
My new mechanic claims it has, but I cannot understand this logic.

The engine is 350 (310hp)....GM I think.
The boat is going into the water on April 23 and then I will check timing, ignition coil, firing order as well as fuel pressure.
I forgot to mention that I changed to new spark plugs - no difference and the previous ones looked fine. Also changed fuel filter 3 times; the mechanic filled in fuel in the filter before mounting. The engine was completely new, incl. ignition cables, distributor, rotor etc.

I will triple check the firing order. The throttle cable seems to to pull all the way. Also tried to manually push the lever on the carburator.

>>Boat running great then looses power and otherwise idles fine. I would like to know what the compression values are, and 100 psi is minimum. I would expect to some at least 140 psi for a new motor.
Boat idles fine and revs in neutral, but will not reach more than 3.000 RPM and with slow acceleration. A compression test was done before the tops were removed and tested. It was then about 13 bar (>180 psi) on each cylinder. Yes, the boat has been running at WOT, but after a short stop, the boat did not go beyond 3.000 RPM.
A BIT MORE HISTORY:
My previous boat mechanic installed a complete new engine in 2015, but engine has had many problem such as white smoke, suddenly dieing, poor starting, irregular idling, complete loss of electricity. At its best the boat was doing 45 kn (appr. 52 mph), but could suddenly die or start reving up and down.

Long story short, I had to change to a new boat mechanic who ended up lifting off both cylinder tops. 2 valves were rusty, but the tops cleared the pressure test. New mechanic claimed that water was sucked in through the exhaust system. The engine was put pack together and exhaust flaps were installed to stop the suction of water.

When putting the boat back in the water, it started but would die immediately. The boat mechanic adjusted the carburetor settings and the boat ran fine for about 3 hours maxing about 34 kn (39 mph). But after resting and taken the boat back, it would not go any faster than 14 kn (16 mph). After that a bunch of troubleshooting / replacement have been done.

 

[alldodge]

The compression was done before the heads (tops) were removed. The 13 bar (180 psi) is way to high for this motor. When pressures start getting this high, your either talking a well built high compression motor, or in most cases there is water in the cylinders.

The white smoke will agree that could very well be water ingestion.

Use to go 45 kn, then after second rebuild it only does 34 kn for 3 hours, then only 14 kn. There is a possibility that when the motor fist ingested water it bent some connecting rods.

Suggest doing another compression test

 

[old islander]

When the complete new engine was installed I wonder how the camshaft was run in. Lots of those symptoms sound like some wiped out cam lobes.

 

[dennis461]

"...14. Engine timing and ignition system operation
Have not tested, but new boat mechanic claims it cannot be timing. "

Sound to me like you need a new mechanic.

 

[jimmbo]

In answer to the power trim issue. An engine trimmed in will force the bow down creating more drag and a heavier load on the engine and the rpms will be lower and since the direction of the thrust is not parallel to the boats direction of travel there is a loss of efficiency, so the boat will be slower.
I think you have multiple problems, and a mechanic that is very quick to, right or wrong blame something he has no responsibility for

 

[aquador]

Thanks for all your help and tips ! Much appreciated.

I will do test when the boat is in the water on April 23 and get back to you.

Unfortunately I chose the wrong company to install the new engine - it has been a complete clown show - so I have no confidence in the new engine was run in properly. I am attaching a few photos taken from before the tops were removed and tested; and one showing water damage to 2 valves on one top.

 

[alldodge]

Sure looks like it was ingesting water for sure

 

[Scott Danforth]

Being the two center cylinders are rusty, did you check the manifolds and risers for leaks?

 

[aquador]

While waiting for the boat to go in the water to test, I a one basic question. Sorry if very basic for you guys.

- Would my mechanis had to remove the distributor or need to adjust the timing due to removing/reinstalling the cylinder tops/heads?

>> Being the two center cylinders are rusty, did you check the manifolds and risers for leaks?
No, the mechanic did not check, but he installed new gaskets everywhere.

Another point perhaps relevant. Before the cylinder tops were removed the engine would rev up and down at idle. Not all the time, but it could easily be provoked, e.g. while docked gently move the boat in gear foreard and back for a split second. If reving higher with the throttle and then back to neutral, the idle would be fine for a while and then be irregular after that. I googled that it could be symptom of leaking gasket at the intake manifod. However, AFTER the tops/heads were reinstalled, I never had that problem. However, the mechanic had to adjust the carbourator idle and mix settings.

 

[Bondo]

- Would my mechanis had to remove the distributor or need to adjust the timing due to removing/reinstalling the cylinder tops/heads?

Ayuh,.... Welcome Aboard,.... Yes, the distributor comes out, before the intake manifold can be removed, which bolts to the heads,...

 

[QBhoy]

Hi
I'm sure there may be other problems underlying, but firstly I would check the tacho and speedo.
Reason I say this is that if it's the same Aquador 22 we get here in the UK, there is no way that boat will do 50mph with a 350.
Perhaps it isn't the same boat, they normally have diesels in them ?

 

[aquador]

Well, finally back after putting the boat back into the water....and with a new mechanic

We removed the flame arrester with running under load and we noticed a clear backfire.

The mechanic checked the fire order order was correct.
Then he checked the basic timing which was 15 BTDC. However, the timing did not change even when reving up to 4.000 rpm, so we suspected a faulty ESTdistributor ignition module. We then reset to base using a home made timing shunt. Adjusted to 10 BTDC. After removing the shunt, the base timing was 15 degree and under load increased to 18-20 degree.

Our next action is to replace the ignition module.

Any other advice? Faulty pick-up coil?

Indmar spare parts are hard to find in Europe. It seems like INDMAR P/N 556096 ignition module is the same as Mercruiser 3854003.
Can someone confirm?

Thanks
// Jens

 

[alldodge]

Then he checked the basic timing which was 15 BTDC. However, the timing did not change even when reving up to 4.000 rpm, so we suspected a faulty ESTdistributor ignition module. We then reset to base using a home made timing shunt. Adjusted to 10 BTDC. After removing the shunt, the base timing was 15 degree and under load increased to 18-20 degree.

Something is missing; Timing is 15 BTDC and reving to 4000 doesn't change anything. Resetting timing to 10 BTDC you can get close to 20 BTDC. Modules don't stop working and then start again.

Being as you were under load there may not be an issue, reason your not getting full advance is because your not getting the rpm high enough.

As for the backfire, since the heads were not checked after water intrusion, I would be looking at a valve and/or seat issue

 

[aquador]

Today, we installed a new ignition module (a copy - not the original Indmar spare part) using a factory timing shunt. Set base to 10 BTDC and advanced showed only 22. Rev'ed the boat while in water and the boat was able to accelerate and go to >30kn, however, if applying full gas, it would backfire during accleration.
So the mechanic manually adjusted the distributor to advanced 32 (base then at 20 BTDC) and the boat accelerated perfectly and >35 kn).
Will test of the boat starts tomorrow when cold.

Is it OK to have the base time set so high?

Do you recommend getting the original Indmar timing module instead?