High oil pressure

[vtmecheng]

I'm sorry to hear that, both about your boat and ACL. That would make anyone depressed. Good luck on both and do your best to stay positive, though I know that's not always easy.

[Mastercrafter]

Couple thoughts. Gas in oil should thin it out and cause lower pressure, not higher. Unless it’s aftuslly a volume of oil issue, but that usually doesn’t cause a pressure issue.

 

Your 1998 Should be fuel injected, not carb’d. Are you mistaking the throttle body injector for a carb?

[Bhaynes85]

No it’s definitely a carb. It’s technically a sport star 19. Sooo paid way to much for the boat lol

[Bhaynes85]

That does make sense about gas thinning out the oil though good thought!! @Mastercrafter

[jepski]

I've been wrong once or twice, LOL......but I'm pretty sure MasterCraft moved to 100% fuel injected GM engines in late '94 or '95 for all boats they produced and Ford dropped it's relationship with Indmar. Really odd that yours has a carb. Here is more detail: "SportStar 19 (1998-2000)

MasterCraft introduced the SportStar 19 midway through the 1998 production year as a closed bow model. MasterCraft developed this model as an entry level boat that set new standards for both quality and performance.The load capacity for the 2,400-pound SportStar 19 is eight people or 1,095 pounds with a fuel capacity of 31 gallons.

In 1998, the SportStar 19 came with the EFI 260 (5.0 L) horsepower engine as standard with a 13x 13 three blade OJ propeller. The engine option of 330 horsepower (LT-1) was offered in 1998.The 1998 model included a black wrap-around windshield frame, unpadded Driver’s armrest,bare fibreglass engine cover, one-colour interior accent, non-removable swim platform brackets,and did not have a trunk. A boat cover was offered as an option in 1998. In 1998 exteriorgraphics for the SportStar were similar to those of the 1995-1997 ProStar"

OK, history lesson over...I would drain the oil, leave the filter and refill with 4 qts of 15w-40. Then run it and watch the oil pressure. Then check oil level. As long as the oil pressure doesn't continue to climb and the oil is within the "safe" zone on the dipstick, I wouldn't worry about it. It could have easily been overfilled, and with 20w/50 could cause a slightly higher reading.

[Andre]

@jepski is right.

Last carb engine used by MC was in 93...unless you got a repowered boat or something...

 

[Andre]

Post a pic of your engine...

 

[Bhaynes85]

 

[jepski]

That’s not a carb engine, it’s throttle body injection (TBI). Confusing b/c it does resemble a carb, but was first generation fuel injection for this era boat. Injectors supply fuel into the intake manifold similar to a carb...but more precise b/c it’s computer controlled by an engine management system. MasterCraft was an early adaptor of EFI, while others continued to offer carbed engine options into the early 2000s I think. That’s a solid, durable engine. If your mechanic can’t or doesn’t want to work on that engine, somethings wrong with him:)

[vtmecheng]

I had one of those GM TBI engines in a truck. It was a really reliable setup. Completely agree with @jepski, any mechanic not willing to work on that engine isn't really a mechanic.

[Bhaynes85]

Well that’s good to know I always thought it looked like a really small carb lol!! The boat is at a much larger mechanic shop/boat dealer now Russell Marine if any of you are familiar with Alabama smith lake area! ALOT more expensive but I don’t think I will have to worry about them deciding in 2 weeks they just don’t want to deal with it!

[jepski]

Just read all of the posts. I didn’t realize you had fuel in the bilge and tore your ACL. really sorry to hear about the injury. And fuel in the bilge is a HUGE danger as everyone said. I’m sure Russell Marine will get you sorted out. Paying more (or going rate) for quality work on a boat is well worth it where safety is big concern. Update when you know more, nothing worse than a thread that fades out with no idea what fixed your problem:)

[LeonL]

As @Gloersen said it may be a failed fuel pump. Some times the fuel can go in the block and it be can also go out, hence fuel in the bilge.. Still don't understand the high pressure.

[Bookm_dano]

I have owned a 1998 Sportstar 19 for a number of years. I have the 305 throttle body engine...looks exactly like the picture posted. Great boat with a very nice wake. The only fuel pump on mine is the electric one on the left rear corner of engine. No connection to inside of crankcase like mechanical pumps. Only time I've had fuel in the bilge was when I failed to tighten a fitting on the pump adequately after some maintenance. I don't think the fuel leak is related to your oil pressure issue. I'd suspect sending unit first then the gauge.

PS - really sorry to hear about the ACL... Wishing you a speedy recovery.

 

[Bhaynes85]

@Bookm_dano thanks for the well wishes! So is my engine the 350gm or a 305 like yours?

[Bhaynes85]

@jepski will definitely let you guys know how this turns out! I feel the same way with threads, a lot of people on MC forum have problems with different things but you never find out how they ended up fixing it bc it just dies out!

[Bookm_dano]

@Bhaynes85 Hard to say for sure. 1998 Sportstar had 305 as standard, 350 as option. I believe later ones were all 350. I don't know an easy way to tell them apart. (I had the heads off of mine a couple of years ago and then it's obvious...but that wasn't so easy.) These engines are about the same as far as reliability and longevity go. The 305 has plenty of juice for my needs. A little caveat: My knowledge of this is mostly from what I read on Mastercraft TeamTalk.

Mostly in This Post

[Bookm_dano]

Hmm... my first attempt at shortening a link.

I'll try again

[Bhaynes85]

Thanks @Bookm_dano that was a good read. My boat came with a 1998 Prostar owners manual but I guess who knows why they had that.

[Bhaynes85]

UPDATE - My mechanic called me today to tell me what all was wrong with the boat and what he did to fix it.

 

He said the gas smell was from a bad thermostat, the engine wasn’t coming up to temperature so more gas was being added then needed trying to get the engine temp up!

 

The high oil pressure was around 8psi lower when he connected a manual gauge. He changed the oil to 15/40 as some of you suggested, and replaced the sending unit. He said the oil pressure isn’t concerning at this point.

 

My water leak was shaft packing, it was pouring not dripping out of the shaft.

 

My ACL is healing well I hope to get the boat soon and at least take her for a ride on the lake before it’s to cold.

 

 

[jepski]

Sounds like it's all good news and you found a new boat mechanic. Heal quickly!

[vtmecheng]

Best case scenario all around. Have fun while you can and look forward to a great 2021 ski season.

[Rikashae]

Hope your injury healed well.

Curious, if there noticeable increase in performance with changed thermostat?

 

I am having the same problems (fuel in exhaust smell) and hoping the fix is as easy fix as thermostat.

[2Valve]

@Rikashae FWIW, I changed from a 140F to 160F thermostat and that resolved the residual fuel odor. Heater works much better also. :)

@Bhaynes85 Glad you got it sorted out. The early TB Chevy's are just about bulletproof, so should be good to go.

[DW]

As the title notes high oil pressure and part of the discussion revolves around excess fuel just a note. The one way oil pressure increases is via higher viscosity oil, and that is pretty much the only way you will raise the oil pressure. Most other things going awry will drop oil pressure except for a malfunctioning sensor or a stuck shut pressure relieve valve (super rare, usually stuck open). When running rich and adding too much fuel, and then diluting the oil with fuel will reduce oil pressure due to the reduction in viscosity with the oil/fuel mix.