PDA

View Full Version : 351 Indmar stalls when put in gear


appleknapil
08-27-2008, 09:12 AM
Help, 1986 351 Indmar stalls when put in gear. Idles Ok and rev good out of gear. Timming @ 6 BTC no vacuum leaks? (at base of carb.) Could this be a power valve issue

appleknapil

Skipper
08-27-2008, 01:09 PM
You said that it idles okay, what is the RPM at idle? I am thinking if it is too low that might be a problem. You describe an engine that seems to be running fine util shifting. So I might suspect other areas. One possibility, a much more complicated problem, might be the shift lever adjustment. The easist way to check that is when the boat is on the water, remove the shift cable at the transmission. Manually shift into gear. If the engine does not stall, the problem is in the shifter.

Covi
08-29-2008, 09:02 PM
Sounds like the carb needs adjusting. My 86' had the same problem recently. carb needed cleaning and adjusting. Does this happen when the engine is warmed up?

jeffjones4
09-03-2008, 11:25 PM
I am new to this forum. My parents recently sold me their 1991 Prostar 190. This has been a great boat over the years for my family and now it is mine. My parents had very few problems with this boat but as luck would have it, age seems to be catching up to the old girl. I recently had the boat serviced after it was spewing black smoke and stalling on me when trying to launch from the dock. That problem has been resolved, but since I have had it back, I cannot seem to just put the boat into gear without it stalling (I have to goose the throttle a little bit to go). Further, it doesn't always start right up. I usually have to push the throttle all the way down once or twice and then turn on the ignition. Generally speaking once the motor is on, it is fine but occasionally it will just die for no apparent reason. We have ski'd behind it the last three times we have had it out but it is annoying that I don't have the control for pulling a skier up smoothly without a slight jerk on the rope when I have to goose the throttle to get it to go. Further, I don't have any control to load the boat onto the trailer because I can just put it in gear to ease it onto the trailer or slowly (and under control) approach the boat dock to pick up my passengers.

I read the post about checking the shift lever adjustment. It is a fairly long way to go to the lake just to check this out. Can I just hook the water intake line up to my hose and do that experiment in my driveway.

Do you have any other suggestions that I might try or look at? If a carburetor adjustment is an option, is this something you can explain how to do? With gas prices the way they are, if it is something I can handle in the driveway then that just leaves more money to ski with.

Thanks in advance for any help.

jeffjones4
09-07-2008, 09:29 PM
Well, I mentioned that I would check the shift lever adjustment. I rigged up a barrel of water and started the boat in the driveway. What I thought was the shift lever adjustment was really the throttle adjustment. All I had to do was make some minor adjustments to provide a little more gas at idle (~1200-1300 rpms) and now I can shift into gear without a stall. Turns out that the engine turns over better on start up with a little more gas too. I will verify this out on the water the next time I get out but I am highly optimistic that I have fixed the problem. Thanks for leading me in the right direction.

Cloaked
09-07-2008, 10:15 PM
Well, I mentioned that I would check the shift lever adjustment. I rigged up a barrel of water and started the boat in the driveway. What I thought was the shift lever adjustment was really the throttle adjustment. All I had to do was make some minor adjustments to provide a little more gas at idle (~1200-1300 rpms) and now I can shift into gear without a stall. Turns out that the engine turns over better on start up with a little more gas too. I will verify this out on the water the next time I get out but I am highly optimistic that I have fixed the problem. Thanks for leading me in the right direction.
No need for a barrel. Just put a water hose nozzle in the intake of the tranny cooler (top side). Turn on the water about half open on the spigget and run it all you want.

Consider tweaking the accelerator pump lever a tiny bit.


.

JimN
09-07-2008, 11:06 PM
1200-1300 is NOT the correct idle speed. In neutral, it should be at about 700 and should maintain that, or close to it, in gear. If it doesn't, either the spark is weak or the fuel/air mixture is wrong.

Cloaked
09-07-2008, 11:45 PM
1200-1300 is NOT the correct idle speed. In neutral, it should be at about 700 and should maintain that, or close to it, in gear. If it doesn't, either the spark is weak or the fuel/air mixture is wrong.Jim, I too have had this issue and would say that the fuel / air mixture isn't the problem (with all due respect). I have one running like this as we speak and have yet to figure it out. It runs perfect, but just dies upon in-gear when getting ready to tighten the rope. It cranks back easily enough, but oddly enough, with the accelerator (in reverse with the neutral switch out), the engine will start not upon acceleration (in the increasing acceleration motion) but it fires upon return to neutral (in the decreasing acceleration motion).


Increasing the idle (RPM) will not correct the issue (in my case, been there already). It just makes it hard on the tranny and indeed, 1200 is too high for an idle.

JimN
09-08-2008, 12:04 AM
Well, there are only a few things needed for an engine to run- Fuel/air, compression and spark (preferably at the right time with respect to the engine's crank position) . If the compression is only fair, it will start but might not keep running in gear. If the spark is weak, the same thing will happen because the fuel doesn't burn fully and this keeps the full power from being developed. If it's not getting enough fuel, all that needs to be done to test this is take a mustard bottle and dribble some gas into the carb as it's put into gear. If it kills faster, we'll know that it's either rich already or the spark is weak. If it runs better, it was lean.

Do these motors have points or electronic ignition? If they have points, have they been checked/set recently for gap and dwell? How old are the plug wires, cap, rotor and plugs?

This should be done after checking the compression and preferably including a cylinder leakdown test or testing the vacuum reading. These should be done after running the engine to normal operating temperature and pulling the spark plugs. Once the general health of the engine is known, the spark intensity and fuel delivery need to be tested.

"It just makes it hard on the tranny and indeed, 1200 is too high for an idle."

Definitely and it's one of the main reasons the idle speed needs to be low. In a car, shifting into gear at 1200-1300 RPM could easily cause it to lurch forward or backward and is a major safety issue. Even though a boat's prop doesn't couple the engine to the ground and provide more or less instant resistance, it's still hard on teh transmission.

jeffjones4
09-08-2008, 09:33 AM
Thanks for all the feedback. I was trying to get the RPMs as low as possible without knowing what they should be. I almost hate to ask this question since I am not a mechanic, but how do you adjust the carburetor or where do you squirt the gas into the carb to test for too lean or too rich? I don't want to blow myself up. I also don't want to damage the transmission. Thanks for everything.

JimN
09-08-2008, 11:35 AM
I use an old plastic mustard bottle with an adjustable spout. To keep it safe, leave the flame arrestor on and have another person shift from neutral to forward. This is just to find out which way the fuel ratio needs to go and any carb work can be dealt with after. Also, smell the exhaust- does it smell like gas all the time, does the transom have black deposits near the exhaust flaps? Obviously, that would indicate a rich mixture. Has the timing been verified and reset, ever? I asked about the ignition- if it has points, the small wedge that rides on the distributor cam does wear, so the gap and dwell will decrease and this kills the spark intensity. Weak spark means that it'll run bad. Cap, rotor, plugs and wires? PCV valve? Timing advance springs and weights working properly?

454Prostar190
09-08-2008, 11:49 AM
I had a similar issue on my S and S... engine dies when I put it into gear.... and found that my rear strut was bent and when I'd put it into gear there was a bind on the strut bushing and the prop shaft. A little throttle and it would be ok and I suppose it eventually wore in and went away:(. When I had my prop shaft replaced earlier this year, the MasterCraft dealer pointed this out and there were wear marks on the prop shaft at the strut bushing location. I had it all replaced and re-aligned and couldn't believe the difference:D. It was something that I would have never thought to check and I think that I know when it happened. I was on tied up on a beach at the Sacramento river, the current put my boat parallel to the sand and grounded the prop, rudder. It took multiple people to get the boat dislodged from the beach. I am careful with my boat but, this was the situation that I think the strut could have possibly gotten bent. Something to think about.

Cloaked
09-08-2008, 10:11 PM
I had a similar issue on my S and S... engine dies when I put it into gear.... and found that my rear strut was bent and when I'd put it into gear there was a bind on the strut bushing and the prop shaft. A little throttle and it would be ok and I suppose it eventually wore in and went away:(. When I had my prop shaft replaced earlier this year, the MasterCraft dealer pointed this out and there were wear marks on the prop shaft at the strut bushing location. I had it all replaced and re-aligned and couldn't believe the difference:D. Interesting note.

jeffjones4
09-09-2008, 12:20 AM
I called the mechanic who got things running to begin with and he verified the timing and changed the plugs (I forgot to ask him whether he change the distributor or not). The cables look new. I don't see any black residue around the exhaust and when I had it running in the driveway I did not really smell any gas and I was at the back of the boat watering the prop while we checked to see if it would stall. As to the points and wedge, I cannot comment yet. I will say that it runs great while pulling a skier. It seems strong and capable. I am 210 lbs and I don't like to start with both feet in the slolam ski because it takes more effort for me and most of the boats I have ski'd behind. The MC yanks me right up (once in gear and not stalled). I found the adjustment screws for the carb and I think I will take it out to the lake and do some adjusting out there to get the RPMs down to where they should be. I will let you know how it goes.

JimN
09-09-2008, 12:45 AM
Where in the Midwest are you located? I would really look at the timing advance weights and springs. If they can't return to their base position, the timing will be too advanced at idle and this can definitely cause bad idle.

clevan
09-09-2008, 02:40 AM
I have an 88 190 and recently had a similar problem. The boat would not die when I put it into gear but would idle rough and hesitate on initial acceleration. Turned out to be low fuel pressure, changed the mechanical pump and it runs great. I think the older boats require a little more attention to the ignition and carb than the newer boats with electronic ignition and fuel injection. Personally that is okay with me since I grew up with these "low tech" engines in my high school hot rods. You don't need to be a mechanic to handle most of the routine maintenance. A few basic tools, a few manuals, and this website. I have also found that while the local dealer can get me parts, they usually don't stock them. I keep an impeller, carb kit, ignition tune up kit, just in case. I have not been able to find an Indmar shop manual but SkiDim had a PCM manual that covered the engine and transmission. You can get alot of info on the carb off the Holley website. If it is giving you trouble at low rpm but is okay at high throttle settings could be a vacuum leak.

jeffjones4
09-09-2008, 09:27 PM
Thanks for the suggestions clevan. How do you test for a vacuum leak? Or...how can you find the leak should you have one?

Skipper
09-10-2008, 08:52 AM
Thanks for the suggestions clevan. How do you test for a vacuum leak? Or...how can you find the leak should you have one?

One technique is to spray starting fluid along the base of the carb while the engine is running. If the engine RPM's increase then there is a vacuum leak. Use the straw on the can so you can more accurately apply the starting fluid.

cmw
09-10-2008, 09:44 AM
I have an 88 190 and recently had a similar problem. The boat would not die when I put it into gear but would idle rough and hesitate on initial acceleration. Turned out to be low fuel pressure, changed the mechanical pump and it runs great. I think the older boats require a little more attention to the ignition and carb than the newer boats with electronic ignition and fuel injection. Personally that is okay with me since I grew up with these "low tech" engines in my high school hot rods. You don't need to be a mechanic to handle most of the routine maintenance. A few basic tools, a few manuals, and this website. I have also found that while the local dealer can get me parts, they usually don't stock them. I keep an impeller, carb kit, ignition tune up kit, just in case. I have not been able to find an Indmar shop manual but SkiDim had a PCM manual that covered the engine and transmission. You can get alot of info on the carb off the Holley website. If it is giving you trouble at low rpm but is okay at high throttle settings could be a vacuum leak.

You can pick up an Indmar shop manual from Amazon.com. I found the link in frequently asked questions. I think it was around $23.