hole shot problems with Merc

[deepsessions]

My boat('82 Ranger 350V Merc 150 XR2) runs at around 5800 at WOT with a 19p stainless prop. With any other prop the boat won't plane. We've tried a 5 blade 23p prop,21,22,23,and the 19. I bought the boat a few months ago with this pre-existing condition thinking we could fix it after checking the compression (130 across the board) and have since had my mechanic clean the carbs,checked the stator,changed the triggers that were semi-melted,try a different fuel pump and bulb,check for wet foam,the boat has been on the water 4 times now and we've come to the end of diagnosing. The boat basically bogs when you drop the hammer and slowly gets on plane after 10 seconds. After that it runs great "like a bat out of hell" my mech says. He did note that the engine has been unbelievably hot before...fusing some wires and metals together.

As it stands I've called every highly recommended boat repair facility and they've all said the XR2's around '85/'86 had jetting problems something about oil collecting in the circulation chamber. My mech had the same boat/motor combo come in with the same problem while my boat was there and he checked the jets to see how they were aligned and then checked mine. They are both the same he'd said and didn't do anything to them. The other boat had stator issues and one of the cylinders wasn't firing...problem fixed.

My questions are can adjusting the jets effect my hole shot? what is risked when doing this? how are the jets adjusted? I've thought about picking the boat up from my mech since he's had it for two months and we are having a hard time figuring out the problem,but he's $60/hr and I've spent most of my money on buying the boat. One shop I spoke to has a dyno would this work for testing the holeshot??

any help is greatly appreciated!

 

[whiplash921]

Re: hole shot problems with Merc

First, the jets do not get adjusted. You buy new ones that are either a bigger or smaller size. Secondly, I know your mech said that he checked the stator, but if one bank is getting weak spark, that will have the same problem you are having. Did your mech check the stator resistance (ohms) or using a DVA (direct voltage adapter)? If he just checked with an ohmmeter, that's not good enough. I have personally seen a stator check fine with an ohmmeter and still be bad. If you are getting spark to all 6 cylinders then the stator will ohm out under mercury specification. If he did check you stator with a DVA, and it checked ok, then I would look at carburetor float issues. Oh yeah, save your self some money and buy a manual. This stuff is not that hard to work on and even easier with a manual.

 

[Scaaty]

Re: hole shot problems with Merc

Whats the plugs look like??...black..drop down a jet size (but easy on the WOT time..)

 

[deepsessions]

Re: hole shot problems with Merc

First, the jets do not get adjusted. You buy new ones that are either a bigger or smaller size. Secondly, I know your mech said that he checked the stator, but if one bank is getting weak spark, that will have the same problem you are having. Did your mech check the stator resistance (ohms) or using a DVA (direct voltage adapter)? If he just checked with an ohmmeter, that's not good enough. I have personally seen a stator check fine with an ohmmeter and still be bad. If you are getting spark to all 6 cylinders then the stator will ohm out under mercury specification. If he did check you stator with a DVA, and it checked ok, then I would look at carburetor float issues. Oh yeah, save your self some money and buy a manual. This stuff is not that hard to work on and even easier with a manual.

not sure how he checked the stator...I will ask him tomarrow.....I bought a Selco manual to better understand the engine but my boat is stored in a dry storage 45 miles from me and I don't have space to work on it.

Whats the plugs look like??...black..drop down a jet size (but easy on the WOT time..)

the plugs are running a little foul. Are engines designed to drop their normal jet size? is this something that happens over time? would this run the engine leaner? he'd said he could make the engine run leaner and give it a faster holeshot but it would make the engine a time bomb and he doesn't want to do it. Is there a way of doing this and staying in a more risk free rpm range?

 

[Texasmark]

Re: hole shot problems with Merc

It does sound like you have other problems, but if you port your prop, your boat will plane out easier and quicker.....plenty of info on here as to how to do it or get a prop shop to do it for you.

Mark

 

[Scaaty]

Re: hole shot problems with Merc

the plugs are running a little foul. Are engines designed to drop their normal jet size? is this something that happens over time? would this run the engine leaner? he'd said he could make the engine run leaner and give it a faster holeshot but it would make the engine a time bomb and he doesn't want to do it. Is there a way of doing this and staying in a more risk free rpm range?

Yep, its a fine line...I'd look at the whole thing again..I don't think messing with the jets is the answer..

 

[deepsessions]

Re: hole shot problems with Merc

still waiting to hear back from my mechanic. I talked to a different one today for some time,and he'd said to leave the jets alone if I'm not at a different altitude from the previous owner. He'd said it sounded like the engine was fine with everything testing out positive. He recommended I raise the engine a notch or two to get the rpm's up(300-500rpms per notch?) and then start testing for prop size. He also recommended a one piece jack plate for tuning down the road.

I've searched beyond belief in regards to my dilemna and haven't come across anything similiar. I appreciate all your guys' help its frustrating trying to diagnose something so far away. Keep the suggestions coming if you will.

 

[Texasmark]

Re: hole shot problems with Merc

Ok, go and get your prop ported, regardless of whatever else you do. You will not regret it.

Mark